The Woolagongs send an agent down to knock out and capture Stitch. His dream beam gun instead zaps Ai, bringing her imaginary friend, Cheng Fei, to life. Cheng Fei takes her to a mythical land in the mountains called the Valley of Dreams, which brings Ai's dreams, good and bad, to life, including a dream of Stitch growing into a monster. Meanwhile, Jumba creates a mo, and Stitch captures the agent that zapped Ai. After Jeijei contacts Jumba saying that Ai was absent from school, the aliens set out to find the little girl.

Stitch decides to be naughty and mass-produce mythical creatures Jumba has been working on. The end result is ruining the nuo opera the town was planning to put on. Cobra Bubbles radios the Galactic Alliance, ready to apprehend Stitch. However, after witnessing Stitch remedy his mistake and gets the creatures to behave and successfully help put on the nuo opera, he calls off the attack.The episode was listed as "Creatures" on DisneyNow when the series was available in the United States.

In this first half of the two-part series finale, Pleakley receives a strange alien device with various functions called a "Tetra-Tab". Ai and Stitch use the device to give themselves "brothers" named "Yong" and "Scratch". They all get along until Scratch starts convincing Stitch to destroy things, getting him to destroy a model city and then a construction site, with Ai, Jumba, and Pleakley finding out about the latter on the local news. After Stitch destroys the construction site, Scratch leads him to a city under construction and convinces him to start destroying it, finally getting Stitch to activate his metamorphosis program and grow into a giant monstrosity. Ai and Yong arrive on Jumba's hovercraft to see the giant Stitch beginning to approach the city.