Set in Australia, four men (Aldo Ray, Neil McCallum, Victor Maddern, Carlo Giustini) escape from prison intending on getting away by boat. But when their boat breaks down before they can get out of Sydney harbor, they take refuge on a small island with an old deserted fort. The island is occupied by a caretaker (Gerry Duggan, a BAFTA nominee for his work here), his wife (Barbara Mullen) and daughter (Heather Sears) who are taken hostage by the men, who then point a huge gun sitting on the parapet toward a munitions boat thus holding the city hostage. A solid minor thriller that manages to build some legitimate tension despite some dubious scenes. The town, for example, is evacuated in record time without any problems. Oddly enough, Aldo Ray as the leader of the escapees is, at first, the most stable of the men then begins to rapidly fall apart without much conviction. Director Harry Watt (who started out in documentaries) keeps the action consistent and well paced but the ending seems too reminiscent of WHITE HEAT. There's not much of Kenneth V. Jones underscore in the film but what there is, is choice. With Alan Tilvern as the Javert like policeman.