Writers: Ed Adamson and Ken Pettus

Jim Phelps: Peter Graves
Paris: Leonard Nimoy
Dana Lambert: Lesley (Ann) Warren
Barney Collier: Greg Morris
Willy Armitage: Peter Lupus

Justin Bainbridge: Andrew Duggan
Howard Bainbridge: Frank Farmer
Vincent Sandler: William Smith
Paul Bainbridge: Anthony Norwalk

The only person knowing the formula of the nerve gas TRA, used in chemical warfare, is Howard Bainbridge, a specialist defected to the East. He is believed to be contaminated by his own chemical and to have escaped the iron curtain to go back to his father, Justin Bainbridge. His father has killed his son and concealed the body. Since there are no records of the formula the only chance to retrieve it is to get samples from the body. The IMF is to retrieve the body.

Justin Bainbridge has buried the body on his estate and is unaware of the fact that his own chief of security, Vincent Sandler, is an agent, who wants to find the corpse, too. Jim comes to the estate as the new private teacher of Bainbridge's grandson, Paul. He gains the boy's sympathy, but not his total trust: The sad boy is heard laughing in an attic where there is officially no access permitted to. Paul won't talk about it. 

While the IMF penetrates into the main house to put up equipment for a holographic show (Barney places projectors in the bedposts, replaces his ring with a duplicate containing a microphone and later Jim puts microspeakers in his ears when he sleeps), Paris and Dana prepare to act as Howard's late mother and Howard himself, Jim pours medicine into Bainbridge's drink. Howard's late wife played the oboe - an instrument still kept in the attic - and soon the elder Bainbridge begins to hear heartbeats and the sound of an oboe. After he repeatedly hears the sounds nobody else hears, he calls in his doctor. Since the doctor is not available another doctor takes over: Paris. 

Bainbridge thows him out when he suggests to eliminate old guilt in order to eliminate the psychological disturbance, but the words get stuck in Bainbridge's mind. Especially after he sees Howard and his late wife appear and ask him to give them peace by burning Howard's body. He rushes out, in the middle of the night and during a thunderstorm, to dig up the body- watched by Sanders and the IMF. All to discover that there is no body. Inside the attic, Paul had frequent visits by Howard. When he is found by the IMF, the sick man explains that he had come back to see his son, but was rebuked by his own father. After a fight, his father attacked him and – thinking him dead – had buried him. Howard managed to get out of the hole in the garden, but he's going to dye. The IMFs convince the sick man to give them a chance to seek remedy by making research on the formula and finding an antidote.