With the fourth piece of the Map of Infinity almost in Aggregor's clutches, the gang chase him through the artificial planetoid known as Perplexahedron.

With Kevin having absorbed Ben's aliens and become insane once again, Ben and Gwen have to go to the null void prison in an attempt to stop Kevin from destroying all the people there. We learn more about how Kevin got his material absorbing powers. In the end Ben thinks Kevin should be put down.