Lieutenant Rip Crandall is duped into taking charge of the "Wackiest Ship in the Navy," which is a true rubbish scow with a crew of misfits who are unaware of the difference between a jib and a jigger. What none of them know, including Crandall, is that this ship has a very critical top-secret mission to perform in waters that are patrolled by the Japanese fleet. Crandall is among those who are unaware of this assignment. If they are successful in their objective, it will result in the saving of hundreds of lives belonging to allies.