AllMovie

Rubber-legged comedian Leon Errol is certainly well cast in Lunatic at Large. Offering a ride to a millionaire, Sam Smith (Leon Errol) agrees to trade places with his passenger for financial reasons. Only when the men in the white coats put the collar on him does Sam realize that the "millionaire" was actually an escaped mental patient. Now an asylum inmate himself, Sam gets mixed up in the plight of fellow patient Bill (Kenneth MacKenna), whose mad twin brother Henry (also MacKenna) is successfully impersonating him on the "outside." With Sam's help, Bill escapes from the booby hatch just in time to prevent the marriage between his sweetheart Beatrix (Dorothy Mackaill) and the duplicitous Henry.