5. Simple

Complete story — includes the ending

Ben is contacted by a little alien girl named Probity who asks him to resolve an ongoing war on her home planet. Despite Kevin and Gwen's reservations, Ben insists they travel to the planet, which they discovered is divided between two warring factions - blue and red - both of which claim that they are merely defending themselves from the other side. Ben eventually learns that the war began over controversy about whether the aliens' idol, Zabin, was red or blue. Ben eventually resorts to capturing the leaders of both factions and insisting that they stop their fighting, but they escape and resume the war. Ben finally intervenes as Way Big, announcing his intention to stay on the planet as long as necessary to ensure peace. However, he accidentally destroys a statue of Zabin, outraging the aliens. The alien factions unite to attack Ben and his team, who flee the planet in shame. Later, Ben receives a message from Probity, who declares that she no longer has a home and now hates Ben more than war. Omnitrix alien debuts: Lodestar