Plot

In the closing days of World War II, Irishman Murphy (Peter O’Toole) is the sole survivor of the crew of a merchant ship, Mount Kyle, which has been sunk by a German U-boat, which then machine-gunned the survivors in the water. Murphy makes it ashore (to a missionary settlement on the Orinoco in Venezuela) where he is treated by a pacifist Quaker doctor, Dr Hayden (Siân Phillips).

When he discovers the U-boat is hiding further up river, under the cover of the jungle, he sets about obsessively plotting his revenge to sink it by any means, including using a surviving Grumman J2F Duck floatplane from the Mount Kyle. The floatplane had been recovered, the wounded pilot later being shot dead in his hospital bed by the U-boat captain, in order to preserve the secret of the sub’s location and, presumably, its action in shooting survivors in the water.