The 2009 "Miracle on the Hudson" saved 150 airline passengers from almost certain death, making instant heroes out of the captain who landed the crippled jetliner in an icy river as well as the crew that guided every passenger to safety. But for Martin Wilkes, whose wife Keira and two sons were aboard that flight, the miracle has a hollow ending: although he and the boys reunite that same day, no one can locate their mother. Keira Wilkes has survived only to disappear. The ensuing search takes her husband far into an Arctic he never knew existed, a breathtaking landscape veiled in a sunless winter. As he struggles through the forbidding cold and suffocating gloom, he begins to understand that it is Keira's emotional darkness-one she kept hidden for years-that has led her there. And he knows also he must now find her before that darkness consumes them both.