Major Bright (Basil Radford) and Captain Early (Naunton Wayne) are two hapless intelligence officers in the British army in post war Germany. Sent back to England for a spot of leave they fail to notice that their new batman is actually war criminal Otto Fisch (Maurice Denham) and when he vanishes the two officers are quickly demobbed. Back on Civvy Street our two heroes set up a private detective agency, 'Bright and Early'. When they are invited to a weekend country house party for a cricket match they stumble across a robbery plot involving a diamond that Fisch has stolen. Will the two detectives finally catch Fisch and recover the diamond?