When zoology professor Cordi O'Callaghan reluctantly accepts an invitation to be a lecturer aboard the Susanna Moodie, a vessel ferrying tourists through Canada's Arctic, she figures it will be a breeze. Seasickness aside, Cordi becomes entangled in the deaths of two of her fellow passengers, both members of a close-knit fiction-writing group. The fatalities are ruled accidental, but Cordi suspects they're anything but. However, she lacks evidence and credibility, according to Martha Bathgate and Duncan McPherson, her sometimes reluctant sidekicks who try to keep her grounded. After Cordi returns to her home in the Ottawa Valley, she hits the trail and stirs up a hornets nest of lies, intrigue, jealousy, and greed as she grills potential murderers, one of whom takes offense and stalks her. Getting marooned on pack ice, a harrowing trip in an airplane and a hot air balloon, and a mysterious fire all add to the menace that threatens Cordi as she attempts to nail down a killer.