Though retired newspaper reporter Henrietta O'Dwyer Collins, Henrie O to her friends, once turned down a marriage proposal from Jimmy Lennox, he's still one of her most cherished friends. So when he asks for her help on behalf of his wife, world-famous documentary filmmaker Sophia Montgomery, Henrie O reluctantly agrees to join them on a Baltic cruise. Sophia is the stepmother to the now-grown heirs of a great fortune, who are none too happy that she controls their inheritance. But do they really want her dead? Jimmy thinks so, and he wants Henrie O to prove it.

On the cruise, Henrie O soon realizes that this dysfunctional family is plunging toward destruction. As the ports of call pass—Copenhagen, Gdynia, Tallinn, St. Petersburg—death inexorably approaches. But Henrie O discovers that love, once kindled, never dies. When Jimmy is accused of murder and time is running out, she pursues a clever killer who won't hesitate to strike again.