Neil Macrae is serving in France under his uncle Col. Geoffrey Wain when his uncle hatches a disastrous plan to advance on the Germans. Neil is later blamed, arrested, and set to be court-martialed when a bomb strikes and he is presumed dead. After recovering from amnesia, Neil returns to Halifax to look for the only person who can clear his name. Alex Mackenzie is a corporal under Col. Wain and the only other person who can vouch for Neil.

Col. Wain is also sent back to Halifax and works as a transport officer. His daughter Penny had been Neil's lover before he went overseas and has given birth to his child, though Neil does not know about that. Penny, believing Neil was dead, began dating Angus Murray but recently deferred his proposal of marriage. Penny and Neil reunite, and Angus, who previously believed the story of Neil's disgrace, agrees to help him find Alex Mackenzie.

Alex is employed at the shipyard, a job Col. Wain helped him to attain, but still agrees to testify to Neil's innocence. However, the Halifax Explosion occurs, killing and injuring several characters. Penny's aunt and uncle who were fostering her child are killed. Angus and Penny are injured. Alex dies from his injuries, but not before Neil secures an affidavit clearing his name. As it turns out, Col. Wain was also killed in the explosion. In the end, Neil and Penny are reunited with their child.