A scientist and his team of underwater explorers search for the culprit who has stolen the world's supply of nerve gas and hidden it somewhere in the ocean.
| Actor | Role |
|---|---|
 Ricardo MontalbanDr. Luis Delgado | Dr. Luis Delgado |
 José FerrerDr. Alfred Vreeland | Dr. Alfred Vreeland |
 Leslie NielsenOfficial | Official |
 Chris RobinsonLedring | Ledring |
 Katherine WoodvilleBarbara Brand | Barbara Brand |
 Lawrence P. CaseyBob Exeter | Bob Exeter |
 Tom SimcoxJerry Hollis | Jerry Hollis |
 Curt LowensEhrlich | Ehrlich |
 Austin StokerBogan | Bogan |
| PPhil PhilbinFirst Technician | First Technician |
 Dan ChandlerSonar Man | Sonar Man |
| TTed SwansonAide | Aide |
 Myron NatwickFirst Reporter | First Reporter |
| HHarlan WardeSecond Reporter | Second Reporter |
| EElisa IngramJean Hollis | Jean Hollis |
| JJoan MurphyNorma | Norma |
| WWilliam EvensonJim Morgan | Jim Morgan |