Hillery receives radiation in her reactor sabotage, & confronting the Capt, falls into the shark tank. Ansara holds the control room hostage with a hand-grenade, while Sterling, in scuba-gear, moves along the exterior top of the sub, while underway. He opens a missle hatch & attaches a launch mechanism. The missle fires, breaches the surface, heading skyward. The flaming belt explodes, ending its threat to earth. Ansara is captured, Pigeon orders the Seaview surfaced, and they pick up Sterling as the flaming sky belt burns out. Pigeon, Sterling, Lorre, & Avalon congratulate each other, & the sub heads home on the surface, with a clear blue sky overhead.