A Merchant Navy hero of the Korean War returns to England after three years of captivity in Communist hands, his mind confused by brain-washing and indoctrination at the hands of his captors, and accepts a post as an instructor at the Outward Bound Sea School.
| Actor | Role |
|---|---|
 Kieron MooreMike Merriworth | Mike Merriworth |
 Sarah LawsonGwyneth Thomas | Gwyneth Thomas |
 Greta GyntMary Griffin | Mary Griffin |
 Mervyn JohnsCaptain Snow | Captain Snow |
 Harry FowlerCharlie Barton | Charlie Barton |
 Anthony NewleyFred Starling | Fred Starling |
 John CharlesworthAndrew Griffin | Andrew Griffin |
 Brian RoperTony Mullins | Tony Mullins |
 Edwin RichfieldNumber One | Number One |
 Ram GopalDr. Tigara | Dr. Tigara |
 Russell NapierRaymond Curtis | Raymond Curtis |
 Mary KerridgeMrs. Snow | Mrs. Snow |
 Don McCorkindaleTubby | Tubby |