After Dennis persuades Pieface that Paul is an undercover super hero, Gnasher, JJ and Rubi go along with the story and help Dennis to 'prove it'. However, his genius plan comes to a sticky end, when Pieface begins to think that with Paul at his side, he is completely invincible!

Gnasher finds a Gnashersaurus rex thigh bone while digging in Beanotown Park! A long lost relative! It's not long before Walter and Dr Pfoofleffer hatch a plan to create a whole new living dinosaur from the bone! Dennis and his pals must save Gnasher's ancestor and hide him in a place where no one will notice a fully-grown dinosaur...