The Enemy of My Enemy

The Enemy of My Enemy is the eighteenth episode of Ben 10: Ultimate Alien.

Plot
Argit infiltrates the Plumbers' Academy with a plan to help the Vreedle Brothers to do the last thing anyone would expect.

Major events

 * We see the Plumbers' Academy for the first time.
 * The Vreedle Brothers appear for the first time in Ultimate Alien.
 * This marks Argit's second appearence in Ultimate Alien. (The first was when Andreas was working for him)

Characters

 * Ben Tennyson
 * Gwen Tennyson

Villains

 * Argit
 * Vreedle Brothers

Trivia

 * This is the first time since Alien Force that the Vreedle Brothers return.
 * This is the second episode Ben and Gwen get to go on a mission alone together without Kevin.