High school senior Ena and security company heir Sakae's deal to fake an engagement may be fooling Sakae's grandparents, but the rest of his strength-obsessed family may not be so convinced. When his cousin Kouki pulls a sneak attack at the apartment Ena and Sakae share, what can they do to show him their love is the real deal?! And if they thought Kouki was dangerous, can Sakae really stand up to the dangers he faces as a bodyguard? Most importantly, how can Ena possibly protect this man she's starting to be tied to by more than just a contract?