King Rat is a novel written by British author James Clavell. It is based in part on the author's own experiences while being held as a prisoner of war by the Japanese during World War II. The novel is set in the Japanese-run Changi prison camp, located deep in the jungle on Singapore Island, during the months leading up to the Japanese surrender and the end of the war. While chronicling the harsh and brutal conditions in Changi – where the POWs are fed only the bare minimum needed to keep them alive and men die every day of diseases and conditions that would be simple to treat in the outside world – the novel also tells the story of the unique friendship that grows between a British RAF Lieutenant named Peter Marlowe and an American corporal called the King. James Clavell, who passed away in 1994, was the author of many novels including Noble House, Shogun, and Whirlwind – all international bestsellers. King Rat was James Clavell’s first novel.

An American corporal known as the King walks back to the hut he shares with the other American POWs at the Japanese-run Changi prison camp after being interrogated by the camp’s British Provost Marshal Lt. Grey. The King is one of the most important and successful black market “traders” in Changi. Although Grey knows about his activities, he has never been able to catch the King in the act. The King passes a young British officer who is speaking to one of the guards in perfect Malay. After he reaches his hut, he sends one of his “employees” out to bring the British man to him. A short time later RAF Flight Lieutenant Peter Marlowe introduces himself. As the two men get to know each other, Marlowe tells the King that he learned Malay while hiding out in a village on Java after his plane had been shot down. As they are talking Lt. Grey comes into the American Hut and almost catches the King with a watch he had “traded” for earlier in the day, but Marlowe lies and covers for the King. Grey leaves empty-handed. When the King tries to pay him for his help, Marlowe refuses and becomes angry; but, the King quickly calms him down. A short time later there is a surprise search of all the huts, and Marlowe returns the hut he shares with other British officers after promising the King that he will come back later that night.

After the search of the huts is over, Marlowe goes to the “bungalow” shared by Colonel Larkin and Mac, his best friends. He tells them about meeting the King. Larkin and Mac tell Marlowe that he needs to be careful around the King. After evening roll call, Marlowe goes back to the American Hut and spends time with the King talking. Near the end of the conversation the King says that from time to time he goes “through the wire” and visits a native village not far from camp. He asks Marlowe if he wants to go with him the next time he goes, and Marlowe says yes. Several days later there is another surprise inspection and this time Captain Yoshima, the Japanese officer in charge, finds the wireless radio he has been searching for in the hut Peter Marlowe shares with a number of other officers. Yoshima places the man caught with the radio under arrest and later sends him to Utram Road Jail, a place rumored to be much worse than Changi. Later that night Marlowe and his friends Larkin and Mac assemble the radio they have kept hidden since arriving at Changi, but when Mac tries to get the news from Calcutta he finds that it doesn’t work.

Several days later Marlowe, the King, and several of the other men in the American Hut catch a male rat, and the King decides that they should find a female rat. They can breed them in a trench under the hut and sell the meat. Three weeks later, the first litter of rats is born. Two weeks after that they let the first two rats – which they have named Adam and Eve – mate again. The King tells Marlowe that they will be going to the village the next night. During the past month Marlowe has been spending a lot of time with the King and thinks they have become friends. Later that night Marlowe serves as an interpreter as the King sells a watch for another prisoner to a Korean guard. He reluctantly accepts a 10% “commission” from the sale, although he feels odd about taking money for doing a friend a favor. The next morning Marlowe goes to see his friend Mac who is recovering from Malaria in the hospital and finds out from him what part of their radio is broken.

The next night the King and Marlowe go “through the wire” to a small village near the ocean where, with Marlowe acting as translator, the King negotiates the biggest deal he has ever made with a Chinese smuggler named Cheng San. It's the sale of a 4-carat diamond. They quickly negotiate a price and agree on the details of the deal, which will be completed later. When they are finished the King leaves Marlowe alone with Sutra, the village headman, while he goes to visit a woman. After telling Sutra about himself and gaining his trust, Marlowe asks the headman if there is an old radio in the village, and Sutra gives him a radio that is in perfect condition. As they are heading back to the village the King notices the radio and becomes angry, telling Marlowe that a radio is the most dangerous thing a prisoner can have and demanding he get rid of it, but Marlowe refuses. After the King calms down he talks Marlowe into only taking the part he needs and burying the rest of the radio, and the two sneak back into camp. The next night Mac uses the part Marlowe has brought him and is able to get the news from Calcutta, which they quickly spread through the camp by word of mouth.

Several days later Mac hears over the radio that the war in Europe is over, and the news spreads quickly among the prisoners. Yoshima turns the camp inside out looking for a radio, but finds nothing. Eve gives birth to another litter of rats, and the King sees that they will need more cages to hold the rats as they grow. He brings an Australian trader named Timsen – his biggest competitor in Changi’s black market – in on the deal and gives him 50% to sell the rat meat when it is ready and to provide the materials to build more cages. A few nights later Shagata – the guard that the King and Cheng San agreed on as a go-between – tells the King that Cheng San has been arrested. The King says that all they can do is stick to their original plan and that he will meet Shagata in a few days to show him the diamond and collect a portion of the money. Two days before this is to happen a tree stump falls on Peter Marlowe’s arm while he is on a work detail. Although the doctor tells him that it is just a flesh wound, the pain in his arm increases. Just before he and the King are to meet with Shagata, Marlowe sees the doctor again and is told that the arm has turned gangrenous and will have to come off soon. When he meets the King he is almost delirious with pain and worry, but the King helps him pull himself together. Then, they go to meet Shagata.

After the King has one of his men fetch the Australian POW who is selling the diamond (and who has Timsen representing his interests) Shagata inspects the stone and sees that it is genuine. He gives the King the down payment and then he and the Australian leave just as Lt. Grey, who has heard from his informer about the deal, shows up. The King and Marlowe are able to get away, but quickly find that most of the camp seems to know about the deal and that there are squads of MPs and gangs of hijackers – some of whom are working for Timsen – after them, trying to steal the money. After realizing there is no way they can escape, the King tells Marlowe to take the money “through the wire” and bury it in the jungle while he distracts Grey and the others. When Marlowe refuses, the King tells him that if he does it and saves the money, he will find a way to save Marlowe’s arm, and Marlowe finally agrees.

The next day the King makes arrangements with Timsen to get the medicine and equipment needed to save Marlowe’s arm. That night Marlowe tries to go back to the jungle to get the money, but he passes out before he even reaches the wire and the King and one of his men carry him back to the American Hut. Timsen arrives a few hours later with antitoxin and administers the first injection to Marlowe himself, then says that he will need an injection every six hours for the next two days. Marlowe receives the injections at Mac and Larkin’s bungalow so that no one else will know about the black market drugs. By the time the injections are finished Marlowe’s arm is almost healed, although he is still very weak. He goes back to his own hut and falls asleep. When he wakes up it is dark, and he is just strong enough to go through the wire and get the money he buried, which he takes to the King. The King pays a small man who has managed to steal the diamond from its original Australian owner half what it would have cost him originally, then takes it back to the American Hut. Almost immediately Lt. Grey and Captain Yoshima come and search the American Hut – Yoshima for a radio, Grey for the diamond – but neither find what they are looking for. The search for the radio that an informer has told Yoshima is in camp intensifies and Marlowe knows it is only a matter of time before they are caught but he, Mac, and Larkin continue to listen to the news from Calcutta every night, and make sure that it spreads through the camp.

Two days later the King goes back to the village alone, delivers the diamond, and is paid more money than he has ever had before. A short time later Captain Yoshima arrives at the bungalow with a squad of guards while Mac, Larkin, and Marlowe are listening to the news from Calcutta and places them under arrest, but leaves the men – and the radio – there with only a single guard after another guard arrives and whispers something in his ear. As they wait, Mac hears that the Americans have dropped an atom bomb on Hiroshima. A few days later the men are still under hut arrest, and Mac hears that the Japanese have surrendered. Mac, Marlowe, and Larkin are brought to see the British Camp Commandant. They are told that the war is really over and that the prisoners will begin to be transported home soon.

Word quickly spreads through the camp and the men in the American Hut – all of whom had been on the King’s payroll – turn their backs on the King and treat him as though he were dead. Because of the surrender, all of the Japanese dollars the King was paid for the diamond are worthless, and suddenly men who had always wanted to do business with him, and who had been on his payroll, want nothing to do with him. Only Peter Marlowe seeks the King out and tells him that they are friends and that he wants to help him, but the King says that he has no friends and tells Marlowe to get lost. Marlowe tries to talk to the King for the next few days but is unsuccessful. When the King climbs on the truck with the rest of the American prisoners to start the journey home he is a broken man, and doesn’t even look at Marlowe as he is waving goodbye. As the novel ends, Marlowe is left with many questions as a result of his strange relationship with the King, including whether the King had ever really thought of him as a friend at all.