The Great Treasure of Tongari Island

This short film debuted in April 2018 and played solely inside the Tokyo One Piece Tower as part of its Luffy's Endless Adventure exhibit, screening with English and Chinese subtitles. Running about eleven minutes, it pairs the post-timeskip Straw Hats with the Heart Pirates and stages a high-energy clash against several Marine heavyweights, built around a mysterious power unique to the island.

The crew lands on Tongari Island and enjoys its food, shops, and casino before following directions Law gave them to a nearby cave. They quickly find a chest, but instead of riches it holds a sleeping Tongari Den Den Mushi, and a furious Nami shakes the little snail awake. Law arrives, insisting the island's treasure legend is real while denying that he summoned them, just as a massive Seastone cage drops over the group and saps Luffy's strength. Kizaru steps out from behind Law, revealing that the swordsman helped him trap the pirates, and Franky answers the crew's distress call.

Franky's Gaon Cannon blast frees them, and the Straw Hats scatter into the forest only to meet a Marine fleet on the coast. Fujitora clashes with Zoro, Sentomaru lunges at Sanji, and Luffy refuses to flee, instead confronting Law. The two trade blows, Law hurling boulders with his Room abilities while Luffy answers with Gear 2 and Gear 3, though Law gains the upper hand by shattering the rocks into a hail of smaller projectiles. Word then arrives through the snail that the Heart Pirates' crew has been rescued, and Law apologizes, the betrayal having been a feint.

Kizaru blindsides both captains, forcing Luffy into Gear 4 Boundman as he and Law struggle against the Admiral. As their friends cheer them on, every Den Den Mushi on the island begins to glow, channeling energy into a central tower that fires a beam of light into the pair. Empowered, Luffy and Law overwhelm Kizaru, and the Marines withdraw. A narrator explains that the island's ancient power is a psychic wave able to amplify Haki, triggered only by strong bonds of friendship, after which both crews reunite to celebrate.

Because it was an attraction-exclusive piece rather than a wide theatrical release, the short was seen only by visitors to the Tokyo One Piece Tower. It leans on spectacle and fan-favorite matchups, lining up Luffy and Law against an Admiral, and ends on the franchise's recurring theme of camaraderie as a literal source of strength.