While hiding in a safe destined for the Moon, Jeannie ends up locked inside. Tony and Roger hire a safe cracker and his helper to get her out. Unfortunately, it appears the safe ends up on the rocket and on its way to the Moon.
It turns out that Roger switched boxes and the safe didn't go to the Moon. Unwilling to take the risk of setting off the explosives, the safe crackers pay a pawnbroker to take it off their hands. She in turn sends it to a scrapyard.
Jeannie tells Tony that, as a full moon has passed since she became trapped, whoever opens the safe will become her new master. NASA gets an expert to open the safe as the explosive component is not working and it is going to detonate.
Tony makes a bet with Roger that Jeannie would never fall for another man. This leads to Tony disguising himself as a British officer. However, things get complicated when Jeannie falls for the "British" officer and Tony becomes jealous.