An insane murderer is on the loose, and gunning for the men who put him away. Will Hay is on the list, and co-opts Claude Hulbert to try and stop him from meeting a grisly end.
Schoolteacher William Potts is the double of a captured German spy, so he is sent to Germany by British Intelligence to obtain the plans of a new secret weapon, causing chaos in a Hitler Youth school in the process.
A man is threatend with scandal when he accidentally acquires a stolen diamond.
