Sgt Major McRuckus catches Private Potts stealing Churchill's cigar butts and orders him to get some books from the library. Colonel Witherton has been invited to Stinky Arbuthnot for the weekend and Stinky might be instrumental in Witherton's promotion. To make a good impression on military buff Arbutnot, Witherton is planning to study the Encyclopaedia of Battles.
Potts brings the heavy book and drops it on Witherton's foot. Unable to walk properly afterwards Witherton orders Potts to go to his house and collect the necessary items for the weekend. Just as Potts has left the office the bookcase collapses and the heavy book falls on Witherton's head.
Potts finds Witherton's home bombed but goes in anyway and starts picking up the items from his list. A neighbour notices him and warns an air warden. The officer believes Potts to be a looter and makes an arrest. Meanwhile Colonel Witherton is diagnosed with amnesia as a result of the bump on the head.
In prison Potts gets a visit from his defense counsel, a stuttering fool who believes Potts is guilty anyway. As Witherton cannot help him, Potts asks to see Vast Vera, a WAF officer who has a crush on him. He seduces the woman and takes her uniform. Dressed as a WAF officer he can walk past the guard, an effeminate man who doesn't notice women, and rush to the hospital.
He desperately tries to make Colonel Witherton remember but has to hide under the bed when McRuckus arrives. A surprised Witherton hits his head on the bedside table when he tries to look under the bed and he regains his memory.
Potts is not completely safe yet because he has to explain wearing the WAF uniform. He pretends to have lost his memory while hiding under the bed.