An unknown maniac threatens to blow up a luxury transatlantic ship, the "Britannic", carrying 1,200 passengers, unless a 500,000 pound sterling ransom is paid. The ship's navigation company sends an anti-bomb squad to defuse seven bombs on board, but the task requires exceptional skill and may be impossible to accomplish.

Juggernaut
A luxurious ocean liner is taken captive by a merciless blackmailer, who threatens to destroy the ship by detonating hidden explosives unless a large ransom is paid.