It's Just Another Beginning

This episode is part of the season,The Vilgaxian Invasions, which is part of the series,Ben 10 Omniverse Season 9.

Plot
Kai and Fistina was picked up from the Plumber Academy by Rook and Ben. But something is happening in Undertown. Radiation levels in Undertown are high. Max is forced to evacuate Undertown. Can Ben, Kai and Rook find out the mysterious source of radiation before the evacuation?