A dog with a spying device under its skin is sent to the Russian government as a present. When the Russians send the dog to a veterinary, British intelligence must get to the dog first and retrieve the spying device.

Laurence Harvey
as Dr. Francis Trevelyan

Daliah Lavi
as Princess Natasha Romanova

Lionel Jeffries
as Stanley Farquhar

Eric Sykes
as Wrigley

Eric Portman
as British Ambassador

Denholm Elliott
as Pond-Jones

Wanda Ventham
as Mrs. Winters

Marianne Stone
as Mrs. Whitby

June Whitfield
as Elsie Farquhar

Colin Blakely
as Russian Prime Minister