The heroine rescues an autistic child and accidentally discovers that the child's adoptive father is a respectable figure (the hero). The child is very close to the heroine, so the hero decides to hire the heroine to protect the child. It turns out that the child is the child of the hero's younger brother, because the hero's younger brother and the heroine The younger brother and sister were chased and killed in a car accident. The male protagonist injured his leg and cut open the belly of the younger brother and sister to take out the child. Later, the female protagonist did her duty and saved the male protagonist several times. The male protagonist initially suspected that the female protagonist had ulterior motives and then gradually fell in love with her.