Hana Mikumo (Kyoko Fukada), born into the "L Family," a family of thieves for generations, falls in love with Kazuma Sakuraba (Koji Seto), the son of a family of police officers for generations. While hiding her true identity, she dreams of living a normal life. Eventually, Kazuma discovers her true identity, but the two overcome numerous difficulties, accept their fate, and finally get married. They are blessed with a child, An, and live happily, despite the problems that arise between their two families. Then one day, Hana's father, Takashi (Atsuro Watabe), declares his "retirement from thievery" after a certain incident. He then gives Hana and Kazuma a slightly belated honeymoon as a gift for all the trouble he has caused them. However, this turns out to be the "L Family's" final job in search of the greatest treasure in history, and a grand adventure that will uncover a family secret that even Hana is unaware of.