Spots 
Edward Prendick survives the wreck of the Lady Vain in an open dinghy alongside two companions. Water shortages drive the men to desperate violence, resulting in both falling overboard during a struggle. Left alone and dying of thirst, Prendick drifts helpless until a passing schooner spots him.
Rescued aboard the vessel Ipecacuanha, Prendick wakes under the care of Montgomery, a disgraced medical student travelling with a cargo of animals. Montgomery feeds him warm broth and restores his strength while remaining evasive about his destination. A silent, misshapen attendant with dark skin and malformed ears attends to their needs.
Prendick encounters Montgomery's sinister assistant on deck and experiences an immediate instinctual repulsion. The man's glowing eyes, pointed teeth, and beastly posture suggest something unnatural beneath his human clothes. Captain Davis, an aggressive alcoholic, rages against Montgomery, his strange cargo, and the grotesque assistant.
The schooner arrives off a solitary volcanic island surrounded by coral reefs. Captain Davis violently unloads Montgomery's menagerie of staghounds, llamas, and caged beasts onto launch boats. Prendick observes the strange, heavy-set natives who arrive to help unload the ship, noticing their awkward quadrupedal movements.
Captain Davis refuses to keep Prendick on board and casts him adrift in a tiny boat without oars. Montgomery initially abandons him, but Doctor Moreau, an imposing white-haired man supervising the island launch, intervenes. They tow Prendick ashore, rescuing him from starvation a second time.
Prendick reaches the island enclave, an enclosed compound of thatched huts and stone walls. The boatmen who landed the cargo display unsettling physical traits, including bent spines, hairy faces, and unnatural gait. Moreau locks Prendick into an outer room of the enclosure, forbidding him from entering the inner courtyard.
Confined to his room, Prendick hears heavy equipment and surgical tools being set up next door. Moreau and Montgomery work in secrecy while locking every connecting door. When Montgomery visits, Prendick presses him about the nature of their work, but Montgomery deflects and warns him against curiosity.
Agonized, humanlike shrieks echo through the compound as Moreau begins vivisecting a newly arrived puma. The screams drive Prendick into intense psychological distress, making it impossible for him to sleep or rest. Horrified by the suffering, he wanders outside into the island forest to escape the noise.
Exploring the jungle, Prendick discovers bizarre hybrid creatures stalking through the vegetation. He finds a decapitated rabbit and encounters a strange, leopard-like humanoid crouched in the undergrowth. Realizing he is being hunted, Prendick flees back toward the compound in terror.
Prendick returns to the compound only to hear screams that sound unmistakably human coming from Moreau's operating table. He concludes that Moreau is performing vivisection on living human beings to create monsters. Fearing he will be Moreau's next experimental subject, Prendick escapes into the jungle.
Moreau, Montgomery, and their hound pack hunt Prendick through the dense forest. Prendick flees frantically through ravines and thickets, desperate to evade capture. He meets an ape-like creature who offers to hide him and lead him to the shelter of the island's beast village.
In a dark volcanic cave, Prendick meets the Sayer of the Law, a large grey creature who leads the Beast Folk in rhythmic chanting. They recite prohibitions against walking on four legs, eating meat, and clawing bark. This rigid social code keeps their animal instincts suppressed and instills terror of Moreau's House of Pain.
Moreau and Montgomery corner Prendick at the edge of the sea. Armed with a heavy stone, Prendick threatens to drown himself rather than undergo vivisection. Moreau explains that Prendick has misunderstood the entire situation and agrees to talk peacefully without weapons.
Moreau reveals his life work: surgically transforming animals into human beings through plastic surgery, blood transfusions, and nerve alteration. Driven by pure scientific curiosity without moral or emotional concern, he seeks the ultimate mastery of living form. He explains that the creatures inevitably revert over time to their animal natures.
Prendick learns the full extent of the island's population, which numbers over sixty modified creatures. Montgomery explains how Moreau instills human speech and habits while suppressing innate instincts. Despite continuous surgical reinforcement, every creature eventually experiences the return of its ancestral animal desires.
Prendick and Montgomery discover half-eaten rabbits, signaling that the Law has been broken. Bloodlust awakens among the creatures, threatening the delicate order Moreau built. The Leopard-Man breaks the ultimate taboo by tasting raw flesh and attacking human authority.
The escaped puma breaks free from her restraints in the laboratory and attacks Doctor Moreau. Moreau pursues the bleeding beast into the forest with a heavy revolver. Gunshots and terrible shrieks echo through the night, ending in a fatal confrontation.
Montgomery and Prendick search the forest and find Doctor Moreau dead, his skull crushed by the puma he had tortured. The dead puma lies beside him, entangled in shrubbery. With Moreau dead, the terror holding the Beast Folk in check disappears.
Desperate and intoxicated, Montgomery burns Moreau's laboratory notes and shares brandy with M'ling and the Beast Folk. A night of wild revelry escalates into chaos outside the compound gates. Montgomery is mortally wounded in a drunken clash with the creatures he befriended.
Prendick finds himself the sole human alive on the island after Montgomery dies. He burns the remaining bodies and compound buildings to maintain the illusion of Moreau's ongoing spirit. Taking up residence among the Beast Folk, Prendick uses fear and deception to stay alive.
Over several months, the Beast Folk shed their human traits entirely, returning to quadrupedal movement, vocal growls, and animal habits. They forget human speech, abandon the Law, and lose their fear of Prendick. Armed with a makeshift spear, Prendick lives as a solitary scavenger.
A small boat drifts ashore carrying two dead sailors, offering Prendick a way off the island. He sails into open ocean and is rescued by a passing vessel after days adrift. Returning to London, Prendick finds human society haunted by the animal instincts he witnessed, ultimately retiring to country solitude to study astronomy.
A shipwreck survivor discovers an isolated Pacific island where a disgraced physiologist turns animals into humanlike hybrids.