Grayson Grimes is an ordinary kid, despite his odd nickname, Grimy. When Grimy’s mom discovers that her favorite childhood vacation spot will be undergoing major renovations, she insists that the family go spend one last summer at Lake Lucy, the way she remembers it.

Grimy is miserable that he won’t be able to attend camp with his best and only friend, Harry. He decides that, even if he must spend his summer at a boring lake with his boring parents, there’s no rule saying that he has to act happy about it. But, to Grimy’s surprise, the trip to Lake Lucy turns out to be far more interesting than he expected.

When Grimy meets a pair of twins with hair the color of maple leaves, goofy Benji, and gorgeous Bunny, he decides that the summer might not be so bad, after all. Still, Grimy becomes wary of the twins when they start communicating with each other as if they can read each other’s minds, and when they begin to tell crazy stories about a spooky tree, in a haunted forest, on the outskirts of Lake Lucy.

In an effort to disprove the ridiculous stories, Grimy convinces his new friends to visit the forest with him. The trio is excited about all the adventuring they could do in the forest over the summer. But soon, Grimy suspects that he might be in danger when his new friends’ tale proves to be more than just a spooky story.