It's another peaceful day in the land of Valley—until Pondside receives a dark and unexpected visitation.

While Helga tries to warn everyone of the coming danger, Goodhill throws Mabel a birthday party.

Mabel and her friends investigate the ruins of Pondside, and find a new ally—along with a few new enemies.

Mabel's band of heroes learns the cause of Maha's rampage, and Ral learns he isn't the only visitor lingering in Bloomburrow.