Bumbling Ernest P. Worrell is assigned to jury duty, where a crooked lawyer notices a resemblance with crime boss Mr. Nash, and arranges a switch. Nash assumes Ernest's job as a bank employee, while Ernest undergoes Nash's sentence to the electric chair. But instead of killing him, the electrocution gives Ernest superhuman powers, enabling him to escape from jail and foil Nash's attempt to rob the bank.
Fletcher Reede is a fast-talking attorney and habitual liar. When his son Max blows out the candles on his fifth birthday he has just one wish - that his dad will stop lying for 24 hours. When Max's wish comes true, Fletcher discovers that his mouth has suddenly become his biggest liability.