It is the greatest mystery of all because no human being will ever solve it.

He was born at 6am on the 6th day of the 6th month. The coming of Armageddon, the site of the final confrontation between the forces of good and evil, as foretold in the Book of Revelations, will being with the birth of the son of Satan - in human form.
Unable to tell his wife Katherine (Lee Remick) the tragic news of their stillborn son, American diplomat Robert Thorn (Gregory Peck) accepts a new born orphan as his son. Details of the child's birth remain a secret but, as the boy Damien grows older, it becomes apparent that he is no ordinary child. As mysterious deaths and strange warnings occur, Robert Thorn slowly becomes aware of the hideous evil behind the child's innocent face and the significance of the number 666, which brings about the most terrifying of revelations.