In the small village of Sueño Bay, famous for its mysterious crystals and legendary moon creatures, friends Ollie, Jenna, Sleeves and Kay are building a go-kart for the annual Fall Fair competition.

Living in the nearby hills are tiny moon creatures, the Hivers, who play a crucial role in the health of the local mushroom crop. But the Hivers' important job is interrupted when Sleeves, the youngest of the group, stumbles upon them. Feeling left out of the go-kart project, Sleeves claims the Hivers as his loyal subjects and locks them away when he's not around. Without the Hivers, the island's mushroom crop starts to take a turn for the worse. Stories say that the last person who messed with the Hivers, the Hillside Hermit, was cursed to roam alone and never return to Sueño Bay. Is Sleeves destined to suffer the same fate or can he and his friends return balance to the island in time?

This is the third book in the Sueño Bay Adventures series, following Shadow Island and Otter Lagoon.