After her father disappears, a teen named Winter becomes the reluctant guardian of a secret portal hidden in the woods, helping lost travelers between time periods make their way back to their own time. But as dark forces turn the woods into something evil, a young man named Henry from eighteenth-century London comes through the portal--with more knowledge of the woods than he should have--and together, they work to find Winter's missing father and discover the history of the forest, which reveals surprising secrets.