Pokémon Scarlet and Violet: The Hidden Treasure of Area Zero

The player is invited to participate in a student field trip to the land of Kitakami. Accompanied by Blair, a teacher guide from sister school Blueberry Academy, the player travels to Kitakami and meets Carmine and her younger brother Kieran, two Blueberry Academy students native to Kitakami. The player is paired with Kieran and tasked with visiting three signs telling the story of "the Loyal Three". Many years ago, an ogre-like Pokémon wearing a Teal Mask named Ogerpon, attacked the land of Kitakami but three Pokémon named Okidogi, Munkidori, and Fezandipiti battled it and died protecting the land. Ogerpon was never seen again, and the villagers buried the three Pokémon in a shrine, named them "the Loyal Three", and held an annual festival to celebrate them. During the festival, Carmine and the player briefly encounter Ogerpon, who drops her Teal Mask before fleeing. Carmine stops the player from telling Kieran what happened, as he idolizes Ogerpon and she fears his feelings would be hurt if he knew he missed a chance to meet her.

The next morning, Carmine's grandfather reveals that Ogerpon was a nice Pokémon who was rejected by the villagers along with her original trainer due to their appearance. However, their ancestor, the village mask maker, took pity on them and gave them four masks; the Teal Mask, the Hearthflame Mask, the Wellspring Mask, and the Cornerstone Mask. Ogerpon and her trainer used them to blend in with the villagers. However, the Loyal Three attacked Ogerpon's trainer and stole three of the masks. Ogerpon killed the three Pokémon, but before she could get the other masks, the villagers scared her away, thinking she was trying to attack them. Carmine decides to make amends with Ogerpon by repairing the Teal Mask. However, they are unaware that Kieran overheard their conversation; the next day, he steals the Teal Mask and angrily confronts the player at the shrine over being lied to his face. After being defeated at the shrine, he gives the mask back. Suddenly, the Loyal Three come back to life (implicitly because of Kieran's anger) and head for Kitakami Hall.

The player and Carmine follow the Loyal Three there, but find that the villagers ignorantly gave the Loyal Three the other masks and mochi implied to be infused with Herba Mystica (as the mochi later cause the Three to grow to Titan size); they then learn that the Three went after Ogerpon which, without any of her masks, is completely defenseless against them. While Carmine heads off to get the Teal Mask fixed, the player goes after the Three and can scare them away. The player and Carmine eventually resolve to help Ogerpon recover her masks, the player bonding with Ogerpon in the process. While the player and Carmine pursue the now Titan-sized Three and defeat each of them, getting the masks back, Kieran tells the villagers the true story and they apologize to Ogerpon. After returning her to her cave, Ogerpon reveals she wants to stay with the player but Kieran demands to battle the player for her. After defeating him, the player successfully catches Ogerpon, leading a distraught Kieran to flee home and lock himself in his room. The next day, Briar announces that she, Carmine, and Kieran must return to Blueberry Academy due to a development regarding Area Zero, so the player and Carmine bid goodbye to each other.

In a post-story scene, Kieran, now consumed by resentment, swears to get stronger and make the player pay for their perceived betrayal of him.

The Teal Mask received "mixed or average reviews", according to review aggregator Metacritic.