In the Forest of the Lost and Found — K.D. Van Brunt

Eighteen-year-old Allyssa Baylor lives a sheltered life of privilege. Not anymore. Now she is lost in the wilderness below the arctic circle with little more than the clothes on her back. A battle is coming and if she's going to survive it, she must lose who she was and discover who she is. 

Ever since her mother's horrible death, Allie wants nothing to do with her family, particularly her sister, Grace, whom she blames for the loss of her mother. But Allie is persuaded to join her family on one last vacation, one last chance to heal the breaches among them before college. The group travels by float plane to a remote lake cabin in northern Canada located 150 miles from the nearest road. 

The vacation becomes a disaster when the plane never returns to retrieve them, and they have no way to call for help. Soon, the food runs out. More ominously, something prowls the woods around the cabin, and they dare not go outside after dark. Finally, desperate and with no other options, Allie resolves to do the impossible: hike through the Canadian wilderness back to civilization and evade whatever predator is waiting in the surrounding forest. 

With her younger sister and brother in tow, Allie sets off into the wild with few supplies and no survival skills. They are not alone. A monster begins relentlessly hunting them. After weeks of running and hiding, the end has come. Allie must overcome the raw fear inside her and make a stand against the beast alone, buying what time she can for her family to escape.