A chance discovery leads American mining engineer Ben Harris and acquaintance Harold to discover a lost city under the sea while searching for their kidnapped friend Jill. Held captive in the underwater city by the tyrannical Captain (Vincent Price), and his crew of former smugglers, the three plot to escape...
| Actor | Role |
|---|---|
 Vincent PriceSir Hugh | Sir Hugh |
 David TomlinsonHarold Tufnell-Jones | Harold Tufnell-Jones |
 Tab HunterBen Harris | Ben Harris |
 Susan HartJill Tregillis | Jill Tregillis |
 John Le MesurierRev. Jonathan Ives | Rev. Jonathan Ives |
 Henry OscarMumford | Mumford |
 Derek NewarkDan | Dan |
| RRoy PatrickSimon | Simon |
| DDennis BlakeHarry | Harry |
| SSteven BrookeTed | Ted |
| JJim SpearmanJack | Jack |
 Tony SelbyGeorge | George |
| MMichael HeylandBill | Bill |
 John BarrettThird Fisherman | Third Fisherman |
 William HurndellTom | Tom |