"The Hunniwell boys and the platinum mystery" by L. P. Wyman is a juvenile aviation adventure novel written in the early 20th century. It centers on brothers Bill and Gordon Hunniwell and Secret Service agent Steve Rogers as they pursue a century-old clue to a hidden cache of precious metal in the Hawaiian Islands. Flying their experimental electric plane, the Albatross, they combine sleuthing with daring flight and face shadowy opposition around Molokai’s rugged cliffs. The opening of this novel follows the boys from a Maine fishing trip to a visit by Rogers, who reveals an 1816 attic letter and map hinting at a stash of metal impervious to nitric acid—likely platinum—hidden on Molokai. They agree to search for it, depart in the Albatross, and make a cross-country-and-Pacific flight marked by a thunderstorm, a ghostly mail-plane encounter, and a close pass over a whale before fog forces a blind landing on a beach. After resupplying in Honolulu, they camp near Laau Point, hear an eerie night wail, and begin searching sea-cliffs between tides. Their battery cells are stolen, but they track down a Japanese thief and recover them; later, someone tries to crush them with a rock from a rift above the shore. Deciding it’s unsafe below the cliffs, they reconnoiter from the air and keep guard—until Gordon vanishes from camp. Finding the plane’s motor brushes removed, they fit spares, take off, and finally spot a hidden hut in a dense thicket, where the opening section breaks off. (This is an automatically generated summary.)

"Hänen viimeinen tervehdyksensä: Muutamia muistelmia Sherlock Holmesista" by Arthur Conan Doyle is a collection published in 1917. This anthology gathers previously published Sherlock Holmes stories, including the titular tale about Holmes' wartime service. The collection features a preface by Dr. Watson assuring readers that the great detective, though long retired and suffering from rheumatism, remains alive and well. Eight cases spanning from 1893 to 1917 showcase Holmes' investigative brilliance across mysterious disappearances, espionage plots, and deadly conspiracies. (This is an automatically generated summary.)

"Ruhtinatar Aurore (»Königsmark»)" by Pierre Benoît is a novel written in the early 20th century. It follows the French officer-scholar Raoul Vignerte, who becomes tutor to a German prince at the court of Lautenburg-Detmold on the eve of the Great War and is drawn into perilous palace intrigues around the elusive Grand Duchess Aurore and the calculating Grand Duke Friedrich‑August. Framed by a soldier’s recollection at the front, the story promises a blend of romance, espionage, and political mystery within a haunted German court. The opening of the novel places a French company in a bleak frontline sector in 1914, where the narrator and Lieutenant Raoul Vignerte settle their men, encounter a dead German from the 182nd Regiment, and the name “Lautenburg” visibly disturbs Vignerte. In a dugout that night, after forced card play and a silent patrol past fresh graves, Vignerte begins his confession. His backstory shifts to 1913 Paris: a stalled academic career, a chance meeting with a well-connected acquaintance who steers him toward a lucrative post tutoring the young Joachim at the Lautenburg-Detmold court, and a cautioned interview with Professor Thierry, who hints at troubling deaths, unusual succession, and the dangerous character of Grand Duke Friedrich‑August. Vignerte then secures the position from the French envoy de Marçais—complete with funds and instructions, even a test in recitation for the poetry-loving Grand Duchess—while Thierry offers sober teaching advice, and departure for the German court becomes imminent. (This is an automatically generated summary.)

"Morgue kadun kauhu" by Edgar Allan Poe is a short story published in 1841. In Paris, two women are found brutally murdered in a locked room—one with her throat cut, the other strangled and stuffed up a chimney. Witnesses heard two voices but cannot agree on the language spoken. Amateur detective C. Auguste Dupin investigates the baffling crime, discovering clues that suggest something shocking: the killer may not be human at all. (This is an automatically generated summary.)

"The new terror" by Gaston Leroux is a novel written in the early 20th century. It appears to be a romantic-psychological mystery with occult overtones, in which a devoted young man, Hector, sees his lifelong love for his cousin Cordélia undermined by an enigmatic English painter whose art exerts an uncanny influence. Themes of hypnotic suggestion, auras, and the idea of a “stolen heart” drive the tension as love, jealousy, and belief collide. The opening of the novel follows Hector from childhood betrothal to Cordélia through his American sojourn and return, where he senses a troubling change in her tied to her art and a mysterious painter. Summoned to the gloomy estate of Vascoeuil, he learns Cordélia and her father have been abroad, sees a shadowy man at Hennequeville, and then hastily marries Cordélia upon their return. At the wedding an unsigned gift arrives: a luminous portrait of Cordélia, clearly by the English painter “Patrick,” which radiates a strange power. That night Cordélia claims she is “as cold as the portrait,” speaks fervently of auras and suggestion, gazes on the painting, and falls into a rigid hypnotic sleep; a local doctor fails, but the specialist Dr. Thurel identifies hypnotic influence and, after blowing on the portrait’s eyes, rouses her. She wakes speaking as if she has shared a moonlit walk and a “golden chamber,” memories that do not match Hector’s reality. The next day she is loving yet altered, and on the second night she is again drawn to the moonlit park, asks Hector to recite Byron as if replaying another man’s words, begs him to save her, and collapses once more into rigidity—leaving Hector terrified that an unseen rival is directing her soul. (This is an automatically generated summary.)

"Missing men by Vincent Starrett" is a detective short story written in the early 20th century. It follows the cool-headed sleuth Lavender as he probes a spate of puzzling disappearances in Chicago. The likely topic is a web of vanishing men tied to the theatre, stage identities, and a family secret that has been carefully hidden. When a picture broker named Peter Vanderdonck, a popular comedian named Charles Merritt, and finally the wealthy Cyril Minor all seem to vanish, Lavender pieces together odd clues: a nearly unused office, greasepaint traces at a washstand, a safe, and a newspaper note about actress Sidney Kane. He deduces that Merritt and Vanderdonck are the same person—and then that Minor is both of them, living a double (and triple) life to avoid publicity while secretly reunited with his former wife, Sidney Kane. A suspicious telegram signed “Father” instead of “Dad” sends Lavender and Minor’s daughter, Shirley, to Kane’s suburban home, where the truth emerges: Kane is Shirley’s mother; she and Minor have remarried, and Minor—struck ill—has been convalescing there under the cover story of an “invalid brother.” The disappearances are thus revealed as a theatrical masquerade rather than crime, ending in a family reconciliation. (This is an automatically generated summary.)

"The adventures of Heine" by Edgar Wallace is a collection of espionage stories written in the early 20th century. The narrative follows Heine, a boastful German secret agent, as he recounts his wartime exploits in Britain with sardonic humor and self-aggrandizing flair. Expect sly reversals, covert schemes, and satirical portraits of both spies and the supposed “enemy,” all filtered through Heine’s unreliable bravado. The opening of the narrative finds Heine reassigned from New York to London at the outbreak of war, where he quickly deploys agents using quirky identifiers and basks in his own cleverness. His star operative, Alexander Koos, courts a Woolwich engineer’s daughter for armament secrets but is outplayed by a young woman from British Intelligence and executed, forcing Heine to flee to Scotland. There, a supposed ally on a Highland hill proves to be a Swiss forger; Heine escapes while his colleague is arrested. Shifted to industrial propaganda in Manchester, Heine funds a fiery labor agitator, targets a chemical firm’s secret grenade plans, and clashes with the enigmatic Miss Harrymore—stealing a march on her by denouncing her as a German spy—only to learn she was actually a German agent, leaving him to spin a face-saving report as the section closes with mention of another captured operative and the introduction of Mister Haynes. (This is an automatically generated summary.)

La marque des quatre by Arthur Conan Doyle is a detective novel written in the late 19th century. It follows Sherlock Holmes and Dr. Watson as they investigate Miss Mary Morstan’s troubling case involving her missing father, mysterious pearls sent annually, and whispers of a hidden treasure tied to soldiers from India. The opening of the novel presents Holmes’s restless intellect and cocaine use, his method of observation and deduction (demonstrated through a revealing analysis of Watson’s watch), and the arrival of Miss Morstan with her story: her father vanished years earlier, she has since received yearly rare pearls, and a new letter invites her to a secret meeting. Holmes and Watson accompany her to the rendezvous, are whisked through foggy London to Thaddeus Sholto, who recounts how his father, Major Sholto, concealed Captain Morstan’s sudden death during a quarrel about a trove from India, hid the treasure, feared a one‑legged man, and died amid a mysterious intrusion marked “The Sign of Four.” Thaddeus explains that his twin, Bartholomew, has just found the treasure in a concealed garret, and the group rushes to Pondicherry Lodge, where a wary gatekeeper and a distraught housekeeper deepen the unease. At the top of the house they find Bartholomew’s laboratory locked; through the keyhole they glimpse his ghastly, frozen face, and as Holmes and Watson break down the door, the scene of the first crisis comes into view. (This is an automatically generated summary.)

"The tomb of Ts'in" by Edgar Wallace is an adventure-thriller novel written in the early 20th century. It centers on a dangerous hunt for the legendary tomb of China’s First Emperor, mixing crime, espionage, and archaeology. The key players include the flamboyant adventurer Captain Ted Talham, the brilliant Italian sleuth Signor Tillizinni, the poised Yvonne Yale, and the ruthless Mr. Soo, all entangled with a murderous secret society and a priceless jade clue. The opening of the story introduces the stakes through repeated attempts to rob a ship’s safe carrying a Chinese Embassy mailbag, leading Tillizinni to the Ambassador, whose historical article about the First Emperor’s burial becomes the catalyst for intrigue. Talham rescues Yvonne from Chinese pursuers in Hyde Park and deciphers the inscription on her ancient jade bracelet—directions that seem to point toward the tomb—before persuading her to let him hold it for safety. Soon after, the Ambassador is found strangled and a Chinese assailant shot dead in a bureau drawer; a vital envelope is empty, and the suave Mr. Soo emerges as a formidable rival, mobilizing his secret-society network. As deceptions multiply—a fake bracelet is swapped, two burglars (Talham and Tillizinni) collide in de Costa’s house, and a bomb nearly kills the detective—the strands tighten around the tomb’s secret, with social niceties masking a deadly contest for the true jade clue. (This is an automatically generated summary.)

"Slighted love : or, At her heart's expense" by Mrs. Alex. McVeigh Miller is a novel written in the late 19th century. It follows Italy Vale, a striking young woman determined to clear her mother’s name after her father’s murder, as she enters her wealthy kinsman’s New England home and confronts old scandals, dangerous secrets, and fraught romances. The story weaves melodrama and mystery around inheritance, social stigma, and the hazards of love, with key figures including the reserved heir Francis Murray, the charming Percy Seabright, and the volatile Mrs. Dunn. The opening of the story reveals Italy’s mother confessing that Italy’s father was murdered and that she herself was tried and acquitted, yet condemned by public opinion; years later, after her mother’s death, Italy goes to Francis Murray’s seaside estate, The Lodge, suspecting him because he benefited from the entail. Tension rises as Italy somnambulates into his library in search of her father’s missing diary, Francis confronts her motives, and she flees to Boston to seek her mother’s old lawyer. There she is deceived by a clerk, Craig Severn, lured to a private house, and nearly assaulted before a mysterious shot kills him; found later walking in her sleep, she is retrieved by Francis and brought back. She meets Percy Seabright—her father’s friend—and faints; newspapers soon report Severn’s body found with a bullet wound. Emmett Harlow gently courts Italy and is refused, while jealous Alys Audenreid and her aunt Mrs. Dunn bristle; during a yacht outing Italy is pushed overboard, rescued by Ralph Allen and Francis, and Mrs. Dunn spitefully accuses Emmett before Francis quells the charge. These chapters set the central quest—finding the truth behind the murder and the missing diary—amid simmering jealousy, peril, and uncertain loyalties. (This is an automatically generated summary.)

"Le cas étrange du docteur Jekyll; Un logement pour la nuit" by Stevenson is a collection of fiction written in the late 19th century. It pairs a Gothic investigation into the bond between the esteemed Dr. Jekyll and the menacing Mr. Hyde with an additional tale likely set in medieval Paris. The main thread follows lawyer Mr. Utterson as he probes the unsettling overlap between public respectability and hidden vice in Victorian London. The opening of the collection introduces Mr. Utterson, who hears Enfield’s story of a cruel, small man named Hyde using a key to a mysterious door and producing a dubious cheque linked to Dr. Jekyll. Troubled by Jekyll’s will that favors Hyde, Utterson seeks and confronts Hyde, confirms his access to Jekyll’s home, and soon learns of the savage murder of Sir Danvers Carew; Hyde disappears, while police find evidence in his Soho rooms. Jekyll disavows Hyde and shows a note, which Utterson’s clerk remarks resembles Jekyll’s handwriting; Lanyon then falls fatally ill after a secret rupture with Jekyll and dies, leaving a sealed packet, while Jekyll grows reclusive. The section ends as Poole, Jekyll’s servant, fearfully begs Utterson to come at once, implying something is terribly wrong behind the locked laboratory door. (This is an automatically generated summary.)

"Ei niin salattua, ettei ilmi tulisi : Tositapahtumiin perustuva kertomus" is a true-event-based novella written in the late 19th century. It appears to be a moral-crime tale set in a small German town, following a generous clockmaker with a hidden past and his devoted foster son as a shocking murder and a fraught investigation test loyalty, justice, and conscience. The opening of the novella introduces Selming, a respected and charitable mechanic–clockmaker living quietly in a South German town, who takes in an orphan, Herman, and trains him; the two form a deep, filial bond. Selming is found murdered, and suspicion falls on Herman after he leaves town early on a secret errand; fragments of a torn letter and a cache of money deepen suspicion. Brought before a conflicted judge, Herman refuses to reveal Selming’s private business, reacts in shock to a knife engraved “Hannu Lobe,” and finally, under torture, falsely confesses, then escapes from a secure cell with mysterious help before being recaptured and condemned. At the scaffold he proclaims his innocence, when an agitated man—Selming’s landlord—bursts in and confesses; he is revealed as Henrik Dorff, also known as Ditlev, an old criminal associate. The judge, now believing Herman, learns Selming’s secret past through papers: Selming was once Hannu Lobe, a repentant former thief whose life turned after a botched burglary, years as a soldier and clockmaker abroad, and a return devoted to restitution. Herman explains his journey and the torn letter were part of Selming’s discreet reparations, and that the prison break was aided by an unknown benefactor. The section closes with the judge disclosing that the landlord and Ditlev are the same man and the true murderer, clarifying the tangled case. (This is an automatically generated summary.)

"The Roman Hat Mystery: A Problem in Deduction" by Ellery Queen is a detective novel written in the early 20th century. It presents a classic closed-circle murder set in a Broadway theatre, where Inspector Richard Queen and his son Ellery investigate the poisoning of a notorious lawyer during a performance. The case hinges on rigorous deduction, suspiciously empty seats, and a missing tophat that turns into the puzzle’s signature clue. The opening of the novel frames the story with a foreword by a friend who recounts retrieving Ellery’s manuscript and sketches the father–son team’s complementary talents. The scene then shifts to the Roman Theatre during the gangster play “Gunplay,” where a commotion reveals an audience member—Monte Field—dead in his seat. Officer Doyle locks down the house; Inspector Queen and Ellery arrive, establish a tight time window (last seen alive around 9:25, found dead about 9:55), and note seven sold-but-empty nearby seats and a conspicuously missing top hat. Early inquiries produce a half-empty ginger-ale bottle (procured by orangeade boy Jess Lynch for Field), a flask, evidence pointing to fast-acting poison, and no gun or stab wound. Usher and doorman accounts suggest no straightforward comings and goings, while a known crook, “Parson” Johnny Cazzanelli, is caught trying to slip out, and Field’s former partner Benjamin Morgan is identified in the audience. The police begin collecting names and ticket stubs, order a painstaking search, and flag the missing hat as a critical lead, with a lexicon of characters and a theatre map signaling a fair-play, clue-driven investigation. (This is an automatically generated summary.)

"Mathias Sandorf" by Jules Verne is an adventure novel published in 1885. When petty criminals intercept a secret message, they expose a Hungarian conspiracy against Habsburg-Austrian rule, leading to arrest and execution. Count Mathias Sandorf escapes and disappears into the Adriatic. Fifteen years later, he resurfaces as the wealthy and mysterious Dr. Antekirtt, commanding an island fortress with advanced weaponry. With two French carnival performers as allies, he navigates the Mediterranean seeking vengeance against those who betrayed his cause and destroyed his friends. (This is an automatically generated summary.)