The Japanese prisoner-of-war camp Changi in Singapore, which houses Allied POWs, is a living hell. The great mass of POWs are living at a sub-human subsistence level. US Army Corporal King has been living up to his surname, through his control of the camp's black market, and by scamming the officers and other POWs. King has a facility for making deals with the Japanese to obtain the contraband he sells to the POWs. His nemesis is British Lieutenant Robin Grey, the camp provost marshal, a humorless, intense martinet who survives through his strict adherence to the British articles of war, which forbid collaboration with the enemy. He is suspicious of King, and is determined to catch him and bring him to justice. The humorless Grey is an upright, uptight moral prig who has been as badly damaged psychologically as any of the other POWs. The high-living King befriends a genteel young British soldier, Peter Marlowe, who at first resists his blandishments, and then succumbs, to his charm. The POWs become aware that the war is drawing to its end, and King and Marlowe grow concerned that the brutal Japanese guards may slaughter the prisoners before they can be liberated. King and Marlowe are determined to raise a large amount of money to buy their freedom by bribing their captors. One of the schemes that King devises is to raise the meat of deer mouse, a native delicacy, to sell to the officers and any POW who can afford it. Conditions are so desperate in the camp, that POWs are stealing rations form one another in order to stave off starvation. This is another one of King's scams, as the "mouse deer' are actually rats, the breeding stock for which have been the rats that have fed off the corpses of dead POWs. The desperate situation in the camp is exacerbated by the brutality of the Japanese guards, and by the senior British officers' predilection for breaking the will of the POWs in order to maintain camp discipline. Resistance, thus, is futile, and with no other outlet, the animosity of the POWs has to be channeled against each other. It becomes quite apparent that, aside from Lieutenant Grey and the dead, everyone in the camp is corrupt. Corporal King merely stands out, as he is Jack-the-Lad, The King-of-the-Hill, King of the Camp, KING RAT.