In the trenches of World War I, Ollie, Stan and the rest of their army company are ready to go 'over the top', but Stan is ordered to stay behind to guard the trench. Scenes of fighting are then followed by the caption 'Armistice'. Twenty years pass, and Stan is still guarding the post, as shown by the huge pile of bean cans he has accumulated, and the path he has worn pacing back and forth on guard. He is found by accident and goes home, feted as a hero. Ollie, who has been married for a year to the formidable Mrs. Hardy, sees him in a newspaper and visits him in the veterans' home. He finds Stan in a wheelchair, having apparently lost a leg, and invites him home. However, Stan is in fact just resting in another veteran's wheelchair and Ollie only finds out he still has both legs after pushing him around in the chair and then carrying him. They reach Ollie's automobile, which he says belongs to his wife and is 'practically new', but Stan quickly manages to completely wreck it. The two men then start to climb thirteen flights of stairs to Ollie's apartment, because they think the elevator is out of order. A man insults Ollie, leading to a lengthy argument. Then they run into a brattish kid with a football, which results in Ollie kicking his ball down the stairwell, leading to another argument with the kid's burly father. When Ollie and Stan finally reach the apartment, Ollie's wife disapproves of Ollie bringing home yet another bum, so Ollie has to prepare a meal for Stan, but the pair only succeed in blowing up the kitchen. Ollie's attractive neighbor, Mrs. Gilbert, offers to help clear up the mess, but herself gets soaked and ends up in a pair of Ollie's enormous pajamas. Mrs. Hardy then returns, so Ollie and Stan have to hide her. When Mrs. Hardy finally leaves, Mrs. Gilbert's husband arrives and when he sees his wife there, he chases Stan and Ollie down the stairs, firing a shotgun. A large number of men jump out of windows.
Block-Heads was the last film directed by John G. Blystone who died shortly afterwards.
The original ending in the script had Billy Gilbert seated comfortably in his study, with Stan and Ollie's heads mounted on his trophy wall. Hal Roach vetoed the idea as "too gruesome", but writer Felix Adler later used the gag at the end of The Three Stooges' 1941 short, I'll Never Heil Again.
