A ship called the Lady Vain was lost at sea. Edward Prendick, one of its passengers, drifted about in the dinghy of the ship for eight days. He was half dead when a vessel called the Ipecacuanha picked him up. A medical man named Montgomery saved his life.
Montgomery and a misshapen companion [M’ling, his attendant] were traveling to the island of Arica with a collection of beasts. During the voyage, Edward incurred the wrath of the drunken captain of the Ipecacuanha. So when they reached Arica and Montgomery and his animals were about to head for shore in a longboat, the captain insisted that Edward disembark with them. To Edward’s dismay, Montgomery refused to take him to the island.
The captain and his men then forced Edward to enter the dinghy of the Lady Vain and set him adrift. When Montgomery saw what had happened, he relented and took him to shore.
Montgomery had brought rabbits to the island for food. His other animals were taken to an enclosure that was off limits to Edward.
Montgomery and his attendant had trouble deciding where their uninvited guest should lodge. They finally put him in a room of the enclosure that had an outer and inner door. The inner door was locked so that David could not enter the rest of the enclosure.
Edward soon learned that the chief personage on the island was named Moreau. After a little thought, he remembered that Moreau was a famous scientist who had achieved notoriety because of his cruel experiments with animals. Because of the adverse publicity, Moreau could not continue his experiments in England; so he left the country.
Soon Edward heard the screams of animals emanating from the area which he was not supposed to enter. He concluded that Moreau was subjecting these animals to vivisection.
The animal screams became so disturbing that Edward left his room and explored the island. He was still exploring when the sun set. In the dark, he was frightened by some creature that was stalking him. He thought that it was a beast, but then he noticed that it was walking upright. He tied a stone to his wrist with his handkerchief. This stone converted his arm into an effective club.
After routing this stalker, Edward was threatened by a smaller creature that moved on all fours. Edward unsuccessfully tried to outrun it. When it was about to catch him, he used the stone attached to his wrist to knock it senseless.
During his exploration of the island, Edward happened to see a grotesque man who walked on all fours like a beast. He had also noticed that that the natives associated with Montgomery were awkward and ugly. M’ling even had pointed ears. When Edward subsequently heard apparently human groans emanating from the enclosure, he jumped to the conclusion that Moreau was practicing vivisection on a human being. Since Montgomery had forgotten to lock the inner door, he entered the forbidden area to investigate. He was soon chased back to his own room, but what he saw seemed to confirm his suspicions.
He figured that the natives of the island looked and acted like beasts because of experiments performed on them by Moreau. Fearing that Moreau intended to perform painful vivisection on him and turn him into a beast man, Edward grabbed a crude weapon and ran away from the enclosure, forcing his way past Montgomery as he left his room.
The fugitive eventually encountered an ape-man who seemed to be friendly. The ape-man led him to a group of huts where he and other beast people were living. Here a gray-haired man, whose title was the Sayer of the Law, said that Edward had to learn the law. Their pedagogical technique was simple. They chanted the laws and compelled Edward to join them.
The laws emphasized that they were men and that they should not perform certain actions that were characteristic of beasts, such as walking on all fours, sucking up drink, and clawing the bark of trees. The laws also forbade the eating of fish and flesh and commanded them not to chase other men. They were also supposed to practice monogamy and honor their master [Moreau].
During these lessons, Montgomery and Moreau arrived on the scene. Edward ran away, chased by Montgomery, Moreau, and the beast men. He ran to the ocean and decided to drown himself. By their assurances and by giving him their revolvers, they persuaded Edward to return with them to the enclosure.
Moreau then explained that he was not operating on human beings. Rather, he was trying to change human beings into men. He managed to give them human qualities by paying special attention to their brains, but they tended to relapse into bestiality. When a subject started reverting, Moreau lost interest and let it go. It was Montgomery who tried to stabilize their human characteristics by teaching them the law and devising the system whereby the beast men could teach the law to their fellows. [The beast men had tried to teach Edward because they thought that he had recently been converted into a man.]
As time passed, Edward became acquainted with the beast men. The most formidable were a leopard-man and a hyena-swine-man. There were also a sloth-like man, a dog-man, and a satyr. There were several swine-men, swine-women, several wolf-like creatures, etc.
The dead body of a rabbit showed that one of the beast men had tasted blood. Montgomery and Moreau considered this a serious matter, since the culprit would thereby become dangerous. They had tried to prevent this by a law forbidding them to eat flesh.
They figured that the leopard-man was guilty. It was, in fact, the leopard man who had stalked Edward when he was alone in the forest at night. However, they first had to prove that the leopard-man was really the culprit.
To learn the truth, Moreau called an assembly of the beast men. As Moreau proclaimed that the offender would return to the house of pain [the enclosure], the leopard man revealed his guilt by attacking Moreau. Then the leopard-man fled with everyone in pursuit. The hyena-swine-man stuck close to Edward as they rain, occasionally casting a sinister glance in his direction.
When they cornered the culprit, Edward felt sorry for the cowering leopard-man. He killed him with his revolver so that he would not have to return to the house of pain.
Edward began to feel sorry for the beast people. His dislike for Moreau’s experiments gradually increased.
The screams that Edward had heard when he first came to Arica had been made by a puma. Seven or eight weeks later, Moreau was still working on the same puma. It managed to escape. It happened to bump into Edward and sent him sprawling. Edward broke his arm in the process.
Moreau ran after the fugitive with a revolver. Thinking that Moreau might need help, Montgomery followed him. He was soon joined by M’ling.
As they looked for Moreau, Montgomery noticed that something was wrong. They encountered two swine-men with tell-tale blood on their mouths. Montgomery cracked a whip at them; but instead of reacting with their usual cowering subjection, the swine-men defiantly attacked Montgomery, who shot both of them. Later Montgomery also shot a small ocelot-man who had blood on his mouth.
Failing to find Moreau, Montgomery returned to the enclosure. He bandaged Edward’s arm. Then he began to drink until he was somewhat inebriated. When Moreau failed to return to the enclosure, the two men began to look for him. They learned that both the puma and Moreau were dead. With the help of some beast men, they brought his body back to the enclosure.
When Edward and Montgomery tried to figure out what to do, they had an argument. Montgomery eventually took refuge in alcohol. Contrary to his normal custom, he invited some of the beast people to join in a drinking party. Things got out of hand, and Montgomery and several of the beast people got killed. When Edward heard the commotion and went out to help Montgomery, he knocked over the lamp, and a fire burned the enclosure.
Edward had to face the beast people alone. By daring bravado, he compelled them to throw the dead bodies into the sea. He tried to kill the hyena-swine-man, who was an obvious threat to his security, but his shot missed, and the beast man got away.
Because he was alone and because fire had ruined the enclosure, Edward’s position was precarious. The friendship of the dog-man proved to be helpful. However, from what Moreau had told him, he knew that the beast men would gradually lose their human characteristics, and this is exactly what happened. Their manual dexterity declined, and it became more and more difficult for them to walk upright. At the same time, their speech deteriorated into gibberish.
At first, Edward lived in the midst of the beast people, but eventually he no longer felt safe among them. He retired to the ruined habitation of Doctor Moreau, which the beast people tended to avoid because of the pain that they associated with this locality. He desperately tried to build a seaworthy raft or boat so that he could leave the island, but he was not skilled at carpentry.
His chief danger was the hyena-swine-man. The evasiveness of this inveterate enemy foiled all his attempts to eliminate this danger. However, after the hyena-swine had lost all semblance of humanity, he killed the dog-man and began to eat him. He did not even run away when Edward approached, but boldly faced his adversary. In the ensuing fight, Edward killed him with his revolver.
Soon after, a sailboat with two dead passengers drifted to the island. Edward gathered whatever provisions he could and sailed away. A brig picked him up, and Edward returned to civilization.
Edward had trouble readjusting to human society. He kept thinking that his fellow human beings were really beasts whose animal nature would eventually reassert itself. After he withdrew from London and began to live in a secluded area, his fears began to subside. With a semblance of contentment, he devoted himself to study.
To write this summary, I consulted a version of The Isle of Doctor Moreau presented online by Classical Authors.