"Couples Retreat" (Season 3, Episode 14) of Ben 10: Ultimate Alien focuses on the contrast between Gwen and Kevin's relationship and Darkstar's manipulation of Charmcaster in Ledgerdomain. The episode culminates in Charmcaster banishing Darkstar after realizing his deception, featuring appearances by Fasttrack, Diamondhead, and Ultimate Humungousaur. For a detailed summary, see the Ben 10 Wiki entry .