It drops you back on Izayoi Island for one contained round, and that's exactly the right dose. The Stitch! series already did the hard work of relocating Disney's blue disaster from Hawaii to the southern tip of Japan, sticking him with Yuuna, a karate-throwing fourth-grader who does not flinch at a talking alien, and dangling the Stone of Chitama in front of him with the cruelest condition in the franchise: 43 good deeds, no shortcuts, and Stitch is constitutionally allergic to good deeds. A one-off special that puts an opponent's name right there in the title is the format at its most honest. No arc to service, no wish counter to inch forward, just Stitch against someone for twenty-odd minutes. Watch it in franchise order, between seasons, the way it was built to be watched.
A special episode of Stitch, taking place between season 1 and season 2.