Dennis and the gang go on a quest to become masters of Blam-jitsu! 

Venturing into the forest, they track down the Beanotown Yeti to learn the secrets of the ancient and untamed martial arts, and find the stash of the Gloop of Greatness. 

But when Bertie and Walter catch wind of what the gang are up to, they decide to hunt the Gloop of Greatness for themselves with a secret weapon – a rocket-powered henchbot! 

Even with the help of the Gloop of Greatness, and the mastery of Blam-jitsu, can Dennis and the gang defeat Walter and free the Yeti?