When Penn and his team are zapped into an old west cowboy world where the cowboys ride dinosaurs, the town sheriff joins them on their mission to prove he still has what it takes.

Penn and his team return to the cowboy world and get help from Sheriff Scaley Briggs to stop Rippen and Briggs' daughter Amber from rustling Cow-o-saurs.

Phil and Rippen tunnel into The Odyssey and damage the Multi Universe Transprojector, causing unbalance in the multiverse. Vortexes form in every world that Penn and his team have visited. Penn, Boone, and Sashi must travel to each world and close all of the vortexes before everything and everyone from all the worlds get sucked into nothingness. During their mission, Penn finds a crystal shard in the nothingness, which, according to Phyllis, is the key to finding his parents.

Penn, Sashi, and Boone must travel to the three most dangerous places in the multiverse in order to free Penn's parents as Rippen plans to conquer the Most Dangerous World Imaginable with Larry and those with him after having to close its portal from the other side.