A young trainer in the Galar region receives their first Pokémon from Leon, the undefeated Champion of the Galar League and older brother to their best friend Hop. Endorsed to take on the Gym Challenge, the player and Hop set out across Galar to earn eight badges and prove themselves worthy of facing Leon in the Champion Cup. Along the way, they encounter rival challengers, the rowdy fan group Team Yell, and the powerful chairman Rose, who oversees both the League and the region's energy corporation. While pursuing the Gym Challenge, the player uncovers a deeper mystery tied to an ancient catastrophe known as the Darkest Day and two legendary Pokémon said to have saved Galar from it long ago. As Rose's ambitions threaten to unleash this power again, the player must confront forces far beyond a simple tournament.