With school out for the summer, The Littles are vacationing in a cabin by the lake, and Stuart is so excited he could burst! But when Snowbell the cat is captured by a mean-spirited creature known simply as the Beast, it's up to Stuart and a skunk named Reeko to rescue him and a few other friends. The Little family spend their vacation near Lake Garland. Meanwhile, in the forest, a beast is threatening the animals to give her food every night.