|James Best||Thorne Sherman|
|Ingrid Goude||Ann Craigis|
|Baruch Lumet||Dr. Marlowe Craigis|
|Ken Curtis||Jerry Farrell|
|Gordon McLendon||Dr. Radford Baines|
Capt. Thorne Sherman lands his ship on an isolated island to make a delivery, only to find that mad doctor Marlowe Craigis is experimenting on shrews there in an attempt to shrink them. The opposite happens, and the shrews become enormous and hungry for human flesh, leaving everyone on the island in peril, including the doctor's pretty daughter, Ann, and her unappealing fiancé, Jerry . Thorne then tries to organize an escape plan.