Am I really the daughter of a thieves family? Hana Mikumo, daughter of the "L family", a family of thieves, unexpectedly falls in love with Kazuma Sakuraba, the son of a family of police officers. She spends her days dreaming of a normal life whilst hiding her true identity. Eventually her true identity is revealed to Kazuma, and after overcoming many difficulties, the two accept their fate and get married. Along with their new daughter Anzu, they manage to live happily, despite the problems that arise between their two families. Then one day, Hana's father announces his plan to retire from thievery after an incident. To make up for all the trouble he has caused Hana and Kazuma in the past, he offers them a late honeymoon trip. However, the trip actually turns out to be the last job of the "L Family", who are in search of the biggest treasure in history, and it becomes a grand adventure that reveals a family secret that even Hana does not know...

Hana comes from a family that has been thieves for generations. Hana refuses to become a thief and she wants to live a normal life. She currently works as a librarian and she is dating Kazuma, who works as a public officer. She hears that Kazuma's family are all public officers. One day, Hana visits Kazuma's family. She discovers that Kazuma's family, including Kazuma, are actually all police officers. Hana gets involved in a case and falls into trouble.