In a hidden world unlike any other, an ongoing battle between the forces of good, who keep the natural world alive, and the forces of evil, who wish to destroy it, takes place. Mary Katherine (M.K.), a teenage girl, finds herself unexpectedly shrunk down to the size of the forest's tiny inhabitants after moving in with her estranged father, who has devoted his life to studying a hidden realm of tiny beings in the forest near their home. As she tries to find a way back to her normal size, she's caught in the middle of the struggle, where she must join forces with a group of warriors known as the Leafmen to save their world — and ours.

Encouraged by the Leafmen and their spirited leader, Ronin, M.K. embarks on an adventure that is as daunting as it is unexpected. Alongside a lovable group of characters, including a comedic slug named Mub, a spirited snail named Grub, and Nod, a rebellious young warrior, M.K. endeavors to stop the malevolent forces led by Mandrake from ruining their world. Their journey reveals the importance of teamwork, courage, and the vital connection between the human world and the natural world, underscoring how every small action can lead to significant changes.