Randy and Howard find a note under their school.

After a power outage at school, a Stankified Monster frozen in ice is freed. When Randy de-stanks him, he and Howard learn that his name is Dickie and his monster form was frozen in ice by the Ninja of 1985. When Dickie (voiced by Bobcat Goldthwait) is saddened by this and how he missed his chance with Tawny (voiced by Annie Potts), The Sorcerer takes the opportunity to re-stank him and find out what is the object of his stank.

When Randy loses the NinjaNomicon, he must save it before hundreds of years of Ninja wisdom is revealed to his enemies.

Randy and Howard must sacrifice everything to prevent the Ninja's ultimate enemy from running amuck.