Seda, sixteen, feels her invisible childhood nemesis, Sawyer, growing stronger just as a group of stranded teens takes shelter from a blizzard in the dilapidated mansion Seda's mother inherited. Seda's mom inherited an old, crumbling mansion, and it was fun to explore the beautiful grounds for a summer. When her mom decided to renovate and live there, Seda isn't happy. And the coming of winter they'll be cut off from the outside world. When a group of teens get stranded near the mansion during a blizzard, Seda has no choice but to offer them shelter, even though she knows danger lurks in the dilapidated mansion-- and in herself.