It's Hallowe'en! Lilo has dressed up as a gory character, while Nani is trying to get everything ready for the trick-or-treaters. Sadly, the house never gets any trick-or-treaters, but Nani wants to fix this. However, Experiment #300, Spooky, is activated, and it can turn into anyone's greatest fear. So, it makes it's way to Kaiaulu Hale's Hallowe'en party, and is terrifying everyone. Can Lilo and Stitch stop it?

Mrs. Hasagawa is watering her vegetables innocently one morning. However, she activates Experiment #613, Yaarp, which is designed to destroy buildings with it's sonic blasts. Lilo and Stitch are hot on it's trail, when it yarps, and because of Stitch's super hearing, Stitch is temporarily deaf. So, when Jumba says only someone with no ears could be safe from Yaarp, Pleakley is on the stage as an Experiment Hunter. Pleakley catches Yaarp, but Stitch's plan to deter Gantu away from the hunt goes wrong, and he captures Stitch. And now he is offering Lilo a trade: Stitch for Yaarp.

Experiment #523 - Slushy

A giant heatwave has struck Kauai. Lilo is trying to get Stitch to try something to escape the heat, but Stitch just refuses: He's a creature of habit, and won't try new things. As he tries to get a cold sofa, he activates Experiment #509, an ice experiment from the elemental series, who has frosty breath that can transform any town into a frozen one.

Experiment 020: SLICK

Chaos ensues as Slick, a fast-talking experiment who can sell anything to anyone, teams up with Lilo and Stitch to sell candy bars for the Hale Kaiulu's annual fundraiser. Lilo soon learns the hard way that Slick is not designed to stop, and she and Stitch must reclaim their household items before it gets too late.

Experiment 234, designed to collect private enemy conversations through her tail, is accidentally activated by Lilo. When she gets into trouble after overhearing part of a conversion and thinking that Mertle hates her friends, Mertle, out of anger, willingly helps catch experiments for Hamsterviel.