When the dam accidentally falls on Norb's head he develops "damnesia" and forgets who he is. Trying to restore his memory, Dag shows him old home videos. A raging "volnado" (half volcano, half tornado) capsizes the Beavers dam during a party. Everyone escapes but Dag and Truckee. Handcuffed together, the two antagonists must escape from the sinking upside down dam. Meanwhile, Norb and the rest of the gang party in the volnado shelter not missing Dag or Truckee at all.