Two kings rule the woods-the Oak King in Summer and the Holly King in Winter-and no mortal may enter their realm without permission. But when Rowan Gwózdek's older sister goes missing, Rowan must search the forest for her, risking the kings' wrath. She enlists the help of her sister's hunting rival Keziah, a trans (and very handsome) hunter with a mysterious connection to the Oak King. He offers to lead her through the forest to find a magical wish granter called the Bear Maiden.

Together, Rowan and Keziah face mossmen, a wood dragon, and other fearsome creatures who serve the Oak King. To make matters worse, Rowan stumbles upon the Holly King, the Oak King's nemesis, and becomes tangled in the conflict between the two kings. To get her sister back, Rowan will have to join in the battle, even if it means she can never return home.