Polo received a letter from his old lover, asking him to come to Baghdad. When he arrived, the other party had already left. In Baghdad, he met Dr. Leidner from the archaeological team and his new wife Louise. Something strange happened. Louise received another threatening letter after marriage, and this was not the first time. She was married before, and then her husband was shot in the war. Fortunately, he did not die, so he sent a threatening letter to his wife while escaping, saying that if she wanted to remarry, he would kill her. Later, her husband died in a train crash. However, just three weeks after she married Leidner, she received another threatening letter. The handwriting imitated Louise's, as if she wrote it to herself. Soon Louise was killed, and only Miss Johnson, the doctor's assistant, saw the murderer. Soon she also died.