Brock guides Ash, May, and Max to the Millennium Festival valley using his guidebook, camping overnight when they find it empty. He applauds enthusiastically during Butler and Diane's magic show, especially a trick transforming Kirlia into Diane, and expresses interest in meeting her. After Team Rocket interrupts the show, Brock learns of Jirachi's existence and witnesses its awakening. When Jirachi teleports snacks into their lodging, Brock devises the solution for Jirachi to teleport the items back to their source. He later joins the group in wearing a clown costume to help maintain cover during Butler's show. Discovering Butler's plan to exploit Jirachi, Brock aids their escape with the Mythical Pokémon. He helps steer Butler's bus towards Forina, Jirachi's home. Brock is present during the climactic battle against Butler's created pseudo-Groudon, getting absorbed by the creature before Jirachi reverses the damage and frees him. Throughout the mission to protect Jirachi and stop Butler, Brock provides steadfast support to the group, departing Forina with them after Jirachi returns to slumber.