The Teal Mask is the first part of The Hidden Treasure of Area Zero, a downloadable expansion for Pokémon Scarlet developed by Game Freak and released in 2023 for Nintendo Switch and Nintendo Switch 2. The expansion sends players on a school trip to Kitakami, a rural region defined by towering mountains, rice paddies, and apple orchards. The area hosts local festivals complete with market stalls and a distinct atmosphere separate from Paldea's familiar surroundings. Players explore this new environment, encounter Pokémon native to Kitakami, form new relationships with characters from other schools, and investigate the region's traditional legends. Access to the main story requires players to have first reached the Treasure Hunt segment in the base game, which takes roughly three hours of play to unlock. The expansion fits within Pokémon's established role-playing framework of turn-based battles and open-world exploration.