In a tribute to Invader Zim, Boinga assumes the role of an Irken invader and moves into the Backyardigans' neighborhood. He masquerades as an average human, using a disguise. However, Uniqua becomes skeptical of the odd behavior Boinga seems to display and discovers that he is truly an alien.
The episode's full recap was previously available at the BackyardigansFans, a forum that has recently closed. The Thingy Majig E may reveal the expanded plot to the Backyardigans Fanon Wiki sometime in the future.