On being given a family tree project Chuckie and Kimi are excited that they only have one piece of homework between them as they are brother and sister. However Kimi discovers her Japanese heritage and decides that she and Chuckie should work on separate projects. At first Chuckie is supportive of her, but after she drags the Finster family into a charade for the school's culture festival, which humiliates them, and then leaves him and Chas out of her project, Chuckie becomes annoyed and wants his old sister back.
Meanwhile Tommy meets a new kid named Trevor. He tries to help Trevor join his group of friends, but when Trevor and everyone else starts to copy Tommy's style and habits, he fears that Trevor is trying to replace him.
Ending Tagline: "Bird poop is thicker than water!" - Chuckie
Chuckie's outfit changes in one scene (where the boys play catch), but then changes back.