'Hunt the Man Down' by Richard Harris

Frank Preston is released from prison after serving a long prison sentence for robbery. He heads directly for his stolen loot, which he previously hid in a sewer, but before he is can get to it, he is confronted by thugs, who beat him up in an attempt to discover the location of the money. Doctor Keel treats Preston for his wounds, but the thugs then assume that Keel knows the whereabouts of the money and so kidnap his assistant Carol. After Preston escapes from hospital, he finds out that his wife, Stella, is involved with the thugs; he then returns to the hospital and forces Keel to help him retrieve the loot. When Preston and Keel arrive at the Sewer, the thugs corner them - luckily, they in turn have been followed by Steed and the police.

Ian Hendry (Doctor David Keel), Patrick Macnee (John Steed), Maurice Good (Paul Stacey), Ingrid Hafner (Carol Wilson), Unknown* (Frank Preston), Melissa Stribling (Stella Preston), Susan Castle (Nurse Wyatt)

Directed by Peter Hammond
Produced by Leonard White

TX:
UK: 8th April, 1961

Notes:
*Featuring Doctor David Keel and John Steed

*The identity of the actor who plays Frank Preston still remains a mystery

*This episode no longer exists