Pirates led by Jonathan Kongre (Yul Brynner), take a lighthouse located on a small rocky island, somewhere in northern Argentina. With the control of the headlamp lights, they execute a terrible plan to disorient the ships and cause them to be aground on the cliffs, thus facilitating their acts of piracy. Will Denton (Kirk Douglas), a member of the lighthouse crew who survives the pirate attack, desperately struggles to regain control of the lighthouse, but the situation is complicated when Arabella (Samantha Eggar), a survivor of one of the ships is taken to the island.