a undercover agent as a singer, protects a family that is in danger. Donghae finds that someone is after his friend Yoochun and his little sister. Chung-Ae an assassinator works for a gang to protect her brother. During a mission Chung-Ae not knowing that Yoochun would be there, accidenly attacks her  brother and Donghae.  Donghae telling yoochun that hes an under cover cop looking for the gang that Chung-ae is working for. Chung-ae has to find a way to get rid of Donghae without Yoochun, D