In the seventeenth century, Sir Simon de Canterville [Charles Laughton] is forced by the Code of Chivalry to duel on behalf of his brother, but flees to the family castle when his opponent engages a substitute—a giant, the Bold Sir Guy. His proud father, Lord Canterville [Reginald Owen], refuses to acknowledge that his son has disgraced the family name, even when shown in front of witnesses where Simon is cowering. The father bricks over the only entrance to his son’s hiding place as proof that Simon is not there, ignoring Simon’s pleas for mercy. Lord Canterville then curses his doomed cowardly son to find no rest until “a kinsman shall perform an act of bravery” in his name, wearing his signet ring.
Next, during World War II, US Army Rangers are billeted in the castle, now owned by six-year-old Lady Jessica de Canterville [Margaret O'Brien]. One of the men is Cuffy Williams [Robert Young]. The Rangers encounter Sir Simon, but rather than being terrorized, they humiliate the ghost with a mock haunting. With Cuffy’s help, Jessica overcomes her own fear of the ghost. Jessica discovers that Cuffy is a Canterville by a distinctive birthmark on his neck. He is a descendant of Sir Simon’s brother. Together, the two meet Sir Simon and learn the fate of their ghostly ancestor. One night, Simon takes Cuffy on a tour of the family portrait gallery, recounting the cowardly act of each descendant. Cuffy scoffs at Simon’s misgivings and boasts that he is different.
However, when the moment of crisis comes, Cuffy seems to be a true Canterville and is paralyzed by fear in combat. On a mission in Europe, he and another soldier are stationed with a machine gun to ambush a large group of Nazi soldiers on motorcycles. Sir Simon appears with the signet ring, which Cuffy had left behind, and his attempts to encourage Cuffy make the young man even more apprehensive. The Nazi convoy appears on the road. His buddy fires and Cuffy feeds the ammunition belt. All seems well until his partner is shot by a sniper. Cuffy moves to take his place, with his friend’s blood on his hand and bullets pinging around him. He freezes, staring, unable to pull the trigger. Another soldier knocks him aside and takes over.
Back in England, Cuffy reports himself. Disgraced and leaving the Rangers for his old outfit, Cuffy is left alone at the castle while the others go out on maneuvers on the huge estate. He is given another chance when Lady Jessica runs to tell him that she saw a parachute land in the woods. She shows him how to drive there. It is an unexploded parachute mine, a blockbuster threatening his platoon and everyone within half a mile with destruction. He springs into action, positioning the jeep to drag the mine to a nearby ravine, but as he hooks the chain to the mine, he is again overcome with fear. Lady Jessica tries to inspire him by kicking the mine frantically, calling “I’m not afraid.” She inadvertently activates the mine. Cuffy recovers, hitches the bomb to the jeep and, after a wild ride with Sir Simon aboard, steers it into the ravine, where it explodes.
The courageous act finally frees Sir Simon from his centuries of bondage, and he can sleep at last in the garden. Lady Jessica and Cuffy lay flowers at Sir Simon’s tombstone (1603–1943). A long time to wait, Cuffy observes. Speaking of waiting, Lady Jessica asks Cuffy how old he is. He doesn’t answer but asks, “Why?” “I shall be 7 in May,” Jessica replies, shyly. He picks her up and they both laugh.
