Dr. Mu's latest hair-brained plan is to invade the Earth using pizza. Harvesting the cheese mountains, giant tomatoes and olive groves of Princess Gelina's homeworld, Dr. Mu has built up the biggest pizza chain in the multiverse. And with his profits he is constructing a giant, pizza-shaped starship called the Death Pizza. Can Rufus escape the clutches of Dr. Mu's pizza-troopers, rescue the princess, destroy the Death Pizza and save the Earth? Well, maybe, but only if he can remember the ingredients of a Four Seasons.

In an attempt to conquer the last free planet in the universe by first winning the hearts of its children, Dr. Mu turns himself into a lovable cartoon character, with disastrous consequences for the inhabitants of planet Earth. To defeat the evil Doctor, Rufus must travel to the cartoon world and become an animated character himself.

Dr. Mu is stealing the internet! With IT systems in meltdown all over the world, Rufus is transported to the doctor's evil HQ, Mu Force One, where he is captured by Dr. Muhahaha and hurled into the internet. In a social networking site called Puffin Portal, he teams up with two fluffy avatars, Buck and Gelina, and together they set out to foil the evil Doctor's plans and restore the internet from its backup server.