A nuclear war specialist returns from a mission gathering data on Soviet communications and electronic warfare techniques in the Arctic Ocean to find that his flat has been broken into and mysteriously re-decorated.

Michael Petrovitch
as Patrick Armstrong

Philip Latham
as Ferdy Foxwell

Don Fellows
as Colonel Schlegel

Michael Gwynn
as Dawlish

Tessa Wyatt
as Sara Shaw

Derren Nesbitt
as Colonel Stok

Nicholas Parsons
as Ben Toliver

Bernard Kay
as Commander Wheeler

John Forgeham
as Security Guard

Stewart Bevan
as Sylvester