When Penelope Culligan agrees to accompany her boyfriend on a camping trip into the wilds of Alaska, so immersed is she in the first throes of love that she barely registers the dramatic majesty of the surrounding landscape. This landscape is brought rather harshly into relief, however, when her beloved David is savagely attacked by a grizzly bear.

David's horrifying accident - and the chain of tragedies it sets into motion - remains the defining incident of Penny's life. Seven years later, she is still traumatized: anguished by the details of David's attack, stalled in an unsatisfying academic program, unable to complete her Ph.D. dissertation.

And now, Penny's own health is deteriorating, for she suffers from juvenile diabetes, a condition that threatens to halve her normal life expectancy, and whose chemical particulars - insulin injections and blood sugar maintenance - virtually control her behavior from hour to hour. Haunted by her past and by her future, Penny is terrified of true engagement of any sort - in particular, of meaningful engagement with other people.

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When Penny embarks on a cross-country bicycle trip back to Alaska, she hopes that this pilgrimage will act as both a symbolic and literal emancipation - from her incapacitating memories, as well as from the prison of her own body's gradually worsening condition. Temporarily free, Penny is at once exultant and vulnerable, newly open to the mysteries and wonders of the natural panorama, of her body's surprising physical stamina, of the compelling strangers she encounters.

When she meets Ndele Rimes, a beautiful and enigmatic fellow traveler who is either the perfect catch or the perfect murderer, Penny discovers that the defenses she's spent so many years constructing have very limited application out on the open road.