The Neptune Factor

When an earthquake on the ocean floor causes an underwater laboratory to fall into a deep trench and places the scientists' lives in peril, Cmdr. Adrian Blake (Ben Gazzara) embarks on a rescue mission in his small experimental submarine. Along with a crew that includes Dr. Leah Jansen (Yvette Mimieux) and diver Don MacKay (Ernest Borgnine), Blake attempts to save the scientists from the unexplored depths, while encountering gigantic sea creatures that threaten their survival.