WARLORDS OF THE DEEP (1978)
KEVIN CONNOR
Plot
Searching for the lost world of Atlantis, Prof. Aitken, his son Charles and Greg Collinson are betrayed by the crew of their expedition's ship, attracted by the fabulous treasures of Atlantis. The diving bell destroyed, a deep sea monster attacks the boat, they're dragged to the bottom of the sea where they're enslaved by an advanced alien race.