Mint is a trainee elf, a "tonttu," at Santa Company's tropical island office. She joined the organization inspired by her older brother, her role model, motivated by the goal of becoming a Santa herself, following his path within the worldwide present-delivery organization.

She trains alongside two peers: Thomas Dou, who becomes her friend, and Noah, her rival. Mint's inherent clumsiness presents a significant obstacle during her early training, causing her to fall behind her cohort and placing her under the shadow of her accomplished brother.

A pivotal moment occurs when Mint, Thomas, and Noah discover extensive ocean pollution accumulating near the island beach. This litter poses a severe danger to the surrounding ocean wildlife and Santa Company's operations, shifting Mint's focus from training challenges to this immediate crisis.

Faced with this threat, Mint demonstrates initiative and resolve, progressing from recognizing the problem to actively participating in cleanup efforts. This real-world challenge tests her perceived shortcomings like clumsiness against the demands of teamwork and perseverance.

Her development centers on adapting to these unforeseen circumstances. While specific long-term changes are not detailed, her actions during the pollution crisis suggest her potential to contribute meaningfully despite initial struggles. The narrative positions this experience as an opportunity for her to potentially "clean up her act," implying growth in responsibility and effectiveness within Santa Company.