Aire, a working-class girl with a special eye for aesthetics, earns her daily living by working as a postal courier.
While searching for a certain item, she attends an auction held at a noble’s mansion—where she instantly spots that forgeries have been mixed in with the auction items!

This discovery draws the attention of Bartlute, the young head of a marquis family who runs the auction, and his associates—
and before she knows it, Aire finds herself caught up in their affairs…!?