Before Madeleine Kimble's mountaineer husband, Aidan, climbs Mount McKinley's south face, he makes her a solemn vow: I will come back to you. But late one night, Maddie gets the devastating news that Aidan has died in an avalanche, leaving her to care for their son—a small boy with a very big secret. The call comes from J. C., Aidan's best friend and fellow climber, whose grief is seasoned with survivor's guilt . . . and something more. J. C. has loved Maddie for years, but he never wanted his chance with her to come at so terrible a cost.

Across the country, Nicholas Sullivan wakes from a motorcycle crash with his memory wiped clean. Yet his dreams are haunted by visions of a mysterious woman and a young boy, neither of whom he has ever met. Convinced that these strangers hold the answers he seeks, Nicholas leaves everything behind to find them. What he discovers will require a leap of faith that will change all of their lives forever.