Ash & co. have gone to Poni Island to work on various research projects. However, Ash is eager to complete his Final Grand Trial and decides to look for the Kahuna, but upon learning there isn't one at the moment, he isn't sure what to do. Soon after that, a trainer named Hapu appears and attacks Ash, thinking Ash has stolen some fruit from the field. To top it off, Team Skull has started to appear on the island. Will Ash be able to clear everything up?

While at Poni Island, Sophocles decides he wants to evolve his Charjabug, so Hapu informs him that the electrical energy around Vast Poni Canyon will allow him to do so. Ash, Kiawe and Sophocles then head to the canyon where they find Horacio and his group who are in the canyon to do the same. At the same time, Lana decides to train her Popplio with her old friend Aya and her recently evolved Primarina. With Popplio learning to properly sing with Primarina, does it count as training? How will everyone's project turn out?