American comedy in which twins Julius and Vincent Benedict (Arnold Schwarzenegger and Danny DeVito) are reunited after being separated at birth. When a government genetic experiment goes wrong, Julius and Vincent are removed from each other and are given their own separate lives. While Julius is deemed a perfect human specimen, Vincent is a pint-sized car thief. When reunited many years later, they both teach each other a thing or two as they set out to find their mother and avoid a hitman who seeks to hunt them down.