As World War Two draws to a close, a sailor aboard ship in the Indian Ocean must do his duty. Watch must be kept, the horizon scanned for enemy craft and the bubble trails of deadly torpedoes fired from stealthy submarines. Haunted and scarred by conflict and the loss of fellow shipmates, our sailor's task is the Middle Watch, or the graveyard watch, as old mariners call it. But, as he goes about his duties, in the small hours of the morning, his routine is shattered by an encounter that could tip the balance of his delicate state of mind.