Young mechanical engineer John Ashton is trying to complete the plans for a new submarine. Under pressure to meet a deadline he has been leaning on whiskey to handle the stress which his friend Robert Gray warns him against, but to no avail. His fiancée, Grace, telephones wanting him to take a break and attend a dinner party with her. Against his better judgement and still drinking he accepts but nods off while getting ready. What follows are booze infused visions of loss and degradation so horrifying that upon awaking he swears off "the devil at his elbow”!