Yuna's mean, bullying cousin Tigerlily (Zuruko) arrives on the island and moves in with her, Stitch, and Gramma. She uses her beauty and fakes kindness to manipulate others. Meanwhile, Hämsterviel plans to use Welco's bubble powers to send Stitch out into the ocean and drown him.

Hämsterviel kicks out five of the weaker experiments and they find their way to Earth. However, Hämsterviel needs them back when it is discovered they stole a treasure chest containing a big secret of the tiny genius.