Professor Oak has finished his research on the mysterious new Pokemon Ash reported and names the new Pokemon Meltan, a Steel-type. One of the Meltan has grown attached to Ash's Rowlet and stows away in Ash's backpack with Rowlet to join them all at the Pokemon School, but after an incident with a Murkrow, it loses its Hex-Nut. Rowlet tries to replace it but nothing he tries seems to work, so he and Meltan head out to find its Hex-Nut. However, they run into Team Rocket, who have found Meltan's Hex-Nut and are still after all the Meltan. Will Rowlet be able to protect Meltan?