Tail is a young, sheltered individual forging an independent life after her mother's passing and her father's frequent absences due to travel. Her father dedicated his life to seeking an ancient treasure, leaving Tail only a pendant and a small castle map as clues upon his death. This treasure hunt becomes her driving motivation, compelling her to embark on a challenging journey.

Fleeing from Tiger, a fierce sea captain with a mechanical arm who pursues both her and the treasure, Tail is rescued by Zorori and his companions. Seeing an opportunity to gain a castle and bride through Tail's quest, Zorori offers his help in locating the treasure. Aware of Zorori's mischievous reputation, Tail accepts the partnership as it advances her goal of uncovering her father's legacy.

Tiger acts as a persistent antagonist, creating obstacles through his relentless pursuit of Tail and the treasure for personal gain. The journey demands navigating challenges tied to the treasure's location while constantly evading Tiger's threats. Through these trials, Tail displays resilience and adaptability, gradually moving beyond her sheltered existence.

The quest culminates in the discovery that Tail's father cherished the adventure and shared experiences with his daughter more than the treasure itself. This revelation transforms Tail's understanding of her father's intentions, highlighting emotional connection above material wealth. Her journey concludes with a deepened appreciation for familial bonds and the personal growth gained.