On a flight to New York for an annual police convention, Chan encounters his old Scotland Yard friend, Hugh Drake. Drake is now a member of military intelligence trying to track down what he believes is a sabotage ring led by a Paul Narvo. A bomber and its pilots crashed the day before. Chan offers his assistance. Chan is welcomed at the airport by New York Police Inspector Vance and, to Chan's surprise, his number two son Jimmy Chan. Chan goes to see Drake the next day at the apartment of George Kirby, where a dinner party is in progress. He finds his friend dead of poison gas in Drake's library, where he had gone to do some work. Drake's briefcase, containing all the information he had gathered about the sabotage ring, is missing. The window is latched, so Chan concludes one of the guests is responsible. Chan discovers that Drake asked that his Oxford classmate Herbert Fenton, actress June Preston and Ralph Percy, chief designer at the Metropolitan Aircraft Corporation, be invited to the party. Kirby himself is the company president. The lost bomber crashed at the company's plant. Also present is stockbroker Keith Jeffery. A servant reports chemist David Elliot insisted on seeing Drake, so he showed him in. Chan learns that Preston also spoke with Drake that night, on behalf of a friend, Patricia Shaw. Shaw, it turns out, married Narvo in India. When she found out Narvo was involved in sabotage, she fled, only to be pursued by her husband and his assistant, Ramullah. Ramullah is eventually tracked down, with Shaw's help, and taken into custody. Before Ramullah can be questioned, however, he is shot and killed. Shaw narrowly avoids the same fate. A coatroom attendant shows up and states Drake checked his briefcase at the club where he works. Chan and Vance wait to see who will claim it. It is Boggs, Kirby's butler. He claims that Kirby left him a note instructing him to get the briefcase. Upon close inspection, Chan concludes it is a forgery. He then discovers Kirby's body. Chan decides to gather all the suspects at the airport the next day. The airplane, rigged the night before to release poison gas when it dives, takes off for a test flight with nearly everyone aboard. As the bomber starts to descend, Fenton grabs the falling glass globe containing the gas. When they land, he smashes the globe, gets out and locks the door. However, the police are waiting to apprehend him, and Chan and the rest emerge unscathed. Fenton cannot be Narvo, as the latter is known to be a younger man. He refuses to identify his leader. When Chan asks for a glass of water for Fenton, Jeffrey gets it for him, falling into Chan's trap. The detective samples the water and identifies the same poison that was found in Kirby's brandy.
