Jealous that Invader Larb is being lauded and rewarded by the Almighty Tallest, Zim seeks an easy conquest on Earth that he can impress them with, settling on taking over the Burrito King restaurant. After kicking out its owner, Burrito Royale, Zim transforms the interior of the restaurant into a throne room, sitting in a throne topped with a giant green sculpture of a mound of beans.
When Burrito Royale returns to reclaim his restaurant, now backed by an army of his own followers and empowered with control over beans, Zim's own barely-supportive minions (who had only been obeying him in exchange for free burritos, which they never got) abandon him. Undeterred, Zim reveals a backup plan - his throne is actually the Mecha-Rito suit in disguise. It quickly activates, and Zim towers over Burrito Royale in it.
However, whatever means of fighting the suit has are never seen, as before Zim has a chance to use it, Burrito Royale and his followers destroy it with a booby trap he had lying around the restaurant. Zim, GIR, and the remains of the suit are then swept out of the Burrito King by a wave of beans.