One fine day, Mary (Rachel Melvin) brings her two friends Jane (Lexi Atkins) and Zoe (Cortney Palm) to the church. My brother is vacationing in a hut in a certain forest. Jane just broke up not long ago, and they hope that their friends can forget all their troubles and sorrows in the leisurely place of clear water and blue sky. The girls are happy and carefree, and soon Jane's boyfriend Sam (Hutch Dano), Tommy (Jake Weary), Buck (Peter Gilroy) and other boys also follow. This holiday seems to have become so beautiful, but a terrible disaster has come quietly.
Previously, discarded medicines from a medical institution accidentally flowed into a valley stream, causing all the local beavers to turn into tyrannical, bloodthirsty monsters. A death trap, no one can escape.
