In present-day Scotland, an American tourist couple go into a bar where they meet an old man who tells them a story about the Loch Ness Monster.
In 1942 Scotland, a boy named Angus MacMorrow lives in the large manor house of Lord Killin on the shores of Loch Ness with his mother Anne MacMorrow (the housekeeper), his sister, a cook, a maid and an old gamekeeper. Later, they are joined by Lewis Mowbray, who comes to work as a handyman in the manor. Angus' father Charlie —Killin's former handyman— is now a sailor in the Royal Navy and has been missing since his ship was sunk in the war a year ago; Angus is unable to accept that it is unlikely he will ever come home.