It's Robin's eighth birthday and it seems like everyone has forgotten. But things take a sudden turn when the Cat-Headed Wanderer shows up and sweeps Robin away to a magical party in a fantastical treehouse. It's a joyful celebration full of song, dance, and newfound friends, but Robin soon realizes there's another reason they've been brought there. To uncover that reason, all Robin needs to do is walk through the half-open door in the back--but what lies beyond?

Rainie Oet's enchanting language and Mathias Ball's stunning illustrations will sweep young readers off their feet, as they follow Robin on this fantastical and deeply moving adventure of discovering themself through the joy of new friends and the memory of loved ones lost along the way.