London, 1860, and crowds flock to witness a hanging. The condemned man is one of the survivors of HMS Melpomene, an Arctic exploration ship whose bitter fate was to be gnawed by ice and swallowed by the depths, with just five men miraculously rescued to return to wonder and acclaim. And now, one of them has murdered his family, with no explanation except his cryptic last words from the gallows: An act done by me against my will is not my act.

Newspaperman Harry Lambert is fascinated by the case. His search for answers takes him to the door of Sidney Blakely: Melpomene carpenter's mate-turned-expedition-leader, and now celebrated Spiritualist medium - a power granted to him, he claims, by the thin veil of the Arctic itself.

But after attending one of Blakely's séances, Harry meets Lieutenant Taylor, who offers Harry his own version of the story of the doomed ship. Blakely tells of courage and conviction, human heroism triumphing against the merciless Arctic. But Taylor's tale whispers of unquiet ghosts, savage beasts, sedition, and strange meat. Harry must tread a dangerous path between them, where what is true and who can be trusted is as shifting and unstable as the ice itself.

Harry knows what Melpomene's crew left in the Arctic. But what did they bring back?