Mint Rondo is a tonttu employed in Santa Company's gift preparation department. She possesses a distinctive mint-colored ponytail. Her older brother, Pedro Rondo, is section chief of Santa Company's SSS bodyguard unit. Mint looks up to Pedro and his skills, motivating her to join the Santa qualification training program on Santa Company's tropical island. During training, she works alongside peers like her friend Thomas Dou and rival Noah. Mint grapples with clumsiness, causing her to fall behind in training and remain in her brother's shadow. A significant event occurs when Mint, Thomas, and Noah discover a large accumulation of litter and plastic pollution on the island's beach. This pollution threatens ocean wildlife and Santa Company's operations, forming the central midsummer challenge. Within Santa Company, Mint assists in wrapping presents, raising reindeer, and supporting the gift delivery process essential to Christmas. Her story highlights environmental awareness regarding ocean pollution.