Accidentally transmigrating into a book and binding with a conquest system, the female protagonist receives a mission: she must conquer the top male lead in the book in order to return home. She goes all out to farm favorability and rack her brains to get close to her target. It is only when the mission is halfway through that she is shocked to discover the system made a recognition error, and the person she is desperately conquering is not the original male lead at all, but merely an inconspicuous extra. The originally aloof and taciturn extra, however, develops true feelings for her through their days and nights together. A hilarious sweet romance triggered by a system blunder begins from here, and the misplaced feelings ultimately turn into a two-way rush toward true love.