Three agents stir up a hornet's nest of greed, betrayal, and intrigue.
George Baker, head of the Secret Service's Far East Division, Colonel Green, his closest aide, and Jim Ellis, special agent, are on the trail of a crime for which there appears to be neither a motive nor a perpetrator. Mildred Beaty, a Secret Service employee in Hong Kong, was the victim of a mysterious murder. Who was she on the trail of? Ellis begins to investigate at the Ivanhoe Hotel, owned by a certain Mrs. Corby, because that is where the murdered woman last stayed. The people who come and go at the Ivanhoe are extremely suspicious: first, there is a pensioner and long-time guest named Philipp Cooper, a lover of Far Eastern music and owner of a beautiful oriental knife; Dr. Hall, a physician and Mrs. Corby's secret lover; and finally, the mysterious butler, John Miller. Another lead leads to the office of real estate agent Tom Clifford...
Mary Jones, who had set a trap for Jim Ellis, is found stabbed to death near Benchley Wood. She had posed to the Secret Service as a contact from Hong Kong. In reality, however, she was the secretary of the real estate agent Clifford, who has his office in the same village where Mildred Beaty was last seen. The murder weapon leads Inspector Bird to the Ivanhoe, because it is the oriental knife belonging to Philip Cooper. On that rainy evening, he is indeed not at home and only returns late from what he claims is a visit to the theater. To the astonishment of everyone present, namely Mrs. Corby, Dr. Hall, Jim Ellis, and the inspector, his knife is hanging on the wall of his room. Meanwhile, a strange journalist named Julie Andrew has also become involved in the investigation...
All leads lead to the "Shanghai," a bar in Cardiff's harbor district. There, Ellis is supposed to meet a certain Batman, who, however, is merely an instrument of the real, unknown mastermind. To Jim's surprise, Batman insists that Ellis bring his coat. The conversation with Ellis is anything but pleasant. Finally, the gangsters capture Julie Andrews in an attempt to soften Ellis up...
