From the title you might think that this is a wartime thriller,but alas it is a whodunit,albeit that in place of the old haunted house the action takes place on a merchantman bound for a convoy. The Captain tricks the main suspects into coming aboard and then casts off when they are on the ship in order to find out who is the guilty party.A few red herrings are thrown in to put you off the trail.However the murderer finally reveals himself as the film uses one of the oldest tricks going.It is all fairly routine.There are lots of familiar faces popping up.Wally Patch plays a steward,Ronnie Shiner a cook,Felix Aylmer a crusty old director of the shipping line ,William (Billy)Hartnell as an engineer,and Hay Petrie as a talkative sailor.If you like whodunits you will probably enjoy this film.