Before that awful Saturday, Molly used to be inseparable from her brother, Hank, and his best friend, Tray. The indoor climbing accident that left Hank with a traumatic brain injury filled Molly with anger. While she knows the accident wasn't Tray's fault, she will never forgive him for being there and failing to stop the damage. But she can't forgive herself for not being there either. Determined to go on the trio's postgraduation hike of the Pacific Crest Trail, even without Hank, Molly packs her bag. But when her parents put Tray in charge of looking out for her, she is stuck backpacking with the person who incites her easy anger. Despite all her planning, the trail she'll walk has a few more twists and turns ahead.