His entire life is devoted to defending the woman he loves. She needs no defense from anyone. He helps her in pursuing justice for her family's deaths. She needs no help from anyone. He vows to himself that he won't ever make her life any worse. She makes a promise to expose the masked individuals who carried out her family's attack and make them pay. He will risk his life for her without expecting anything in return, but she has no time for love because all she loves is justice. But what if he finds out that the person she's looking for is connected to him? Will he guard her heart while defending her life? This action-romance-drama-comedy tells the story of two people who carry out their dangerous missions with bullets and go on a life-or-death adventure.