Lei Lin arrives at a struggling swordsmanship dojo, claiming lineage through her father's friendship with the previous master. She joins the small group of young women residing and training there during a period of decline following the master's sudden departure, contributing to the changing dynamic.

Her connection to the dojo's history is established through her father's past relationship. She actively trains alongside Shinjuro Tateoka and the others. When the shogunate tasks the dojo with patrolling the city against burglaries linked to the rogue samurai Mikage – thieves seeking a powerful stolen government sword – Lei Lin participates fully.

She is involved in the group's efforts to protect the town from Mikage's forces as the thieves' ambitions grow. Lei Lin supports the main protagonist in the conflict while adapting to life within the unconventional dojo environment. Her interactions include participating in lighthearted moments, notably a recurring comedic situation stemming from an accidental physical encounter between Shinjuro and another female character, which becomes a source of ongoing humor.