"The Nutshell" is the fourth episode of the third series of the 1960s cult British spy-fi television series The Avengers, starring Patrick Macnee and Honor Blackman. It was first broadcast by ABC on 19 October 1963. The episode was directed by Raymond Menmuir.[2]
Steed and Cathy investigate espionage by a pretty burglar in "The Nutshell", codename for a top-secret underground nuclear shelter.[3] They are not telling each other everything, and somewhere a traitor lurks.