Paul Brandon is a half white, half southeast asian man in a hospital in Myanmar, in the fever ward. He begins to tell the story to his nurse of how he ended up in the hospital. Paul was born in London, and came to a town named Karen a year or two prior to trade. A man named Pra Oom Bwaht approaches him one day and offers to show him the Temple of Siva in the town. Paul agrees. In the temple is a girl named Nagy N'Yang, who Paul is attracted to. Pra Oom Bwaht tells Paul to follow her down the path to her hut, which he does.
That night Nagy and Paul go back to the temple together. Nagy sits on a chest. Paul asks her to marry him, which she says is impossible. A priest comes in, and something in the chest stirs. A giant python emerges, which Nagy strokes and holds, then puts back in the chest. The priest reveals that Nagy may not wed because she belongs to Siva, and that she was previously wed but on her wedding day the temple claimed her. She will be free if someone kills the python, but it must not be a friend of the husband. The priest tells Paul that even if he takes the girl, the priest can call her back or kill her using a scale from the snake in the chest. Paul goes to leave the temple with Nagy, and there is a cobra in the doorway. Paul steps on its head and kills it, and the priest places the Curse of Siva on him.
Paul takes Nagy and they go to a different town down the stream. One day, Pra Oom Bwaht enters. He says he that Nagy is his sister, so Paul welcomes him in. Later, Paul goes to the house that Pra Oom Bwaht has gotten in the town, and Pra Oom Bwaht does not offer him a seat. Paul goes to his friend Ali Beg's house. Ali gifts him a throwing knife. Great rains begin, and the river starts to flood. Paul and Nagy plan to leave the town shortly when the river lowers. Pra Oom Bwaht comes to their house again, and gives Nagy a small gold item. He says they have family matters to discuss, and Paul allows Nagy to go with him. 
When he is in his house, Paul is suddenly hit over the head with an object and knocked unconscious. When he wakes, Pra Oom Bwaht is standing over him with a knife. Pra Oom Bwaht reveals that Nagy was his wife, and they had planned to let Paul kill the snake so Nagy could be freed and go with Pra Oom Bwaht. Instead, she had fallen in love with Paul, so Pra Oom Bwaht had placed the scale of the snake in her hand. He also reveals that he has bound Nagy to a large log on the edge of the river. Pra Oom Bwaht tries to stab Paul, but Paul kills him first. He goes out to the river, where he sees Nagy bound to the log, which has moved to the middle of the stream and is stopped by rocks. He searches in the dark to try to find a boat to save her. Instead, he finds a chest, which he opens. A large python comes out and disappears into the river.
Paul tries to drag the chest into the water to use as a boat, but it is too heavy for him. So, he dives into the river. When he touches Nagy's raft, it is dislodged and moves towards a whirlpool. They start to swirl downwards into the whirlpool, and then they begin to rise. When they come up, the python is wrapped around Paul and pressing him into the roots. It strikes Paul with its head, and when it reaches back to strike again, Paul kills it with a dagger.
In the hospital, Paul learns that Ali Beg found him and Nagy together on the raft. Nagy was clutching the scale, which Paul tells the nurse to burn. Ali Beg and Nagy are also at the hospital, and Paul tells the nurse to wheel their cots together. He also tells her that he will not go up-country again, because when he and Nagy have their first child together he wants it to be born out of the shadow of the Curse of Siva.