A police captain poses as the valet of a friend who has been invited on a yacht cruise by a notorious schemer, whom the friend is afraid wants to murder him.
| Actor | Role |
|---|---|
 Jack RaineCapt. Roger Peel | Capt. Roger Peel |
| JJean ColinSylvia Paget | Sylvia Paget |
 Jameson ThomasVernon Wolfe | Vernon Wolfe |
 Randle AyrtonCaptain MacDonnell | Captain MacDonnell |
 Carl HarbordArthur Wardell | Arthur Wardell |
 Henry VictorCount Boris Ivanoff | Count Boris Ivanoff |
 Allan JeayesDr. Saunders | Dr. Saunders |
| MMaria MinettiCountess Olga Karova | Countess Olga Karova |
| CCharles DormerNigel Menzies | Nigel Menzies |
 Ivo DawsonColonel Paget | Colonel Paget |
| EEdna DaviesLisette - Maid | Lisette - Maid |
 Syd CrossleyNot listed | Not listed |