Regional Crime Unit officer Chan Kwok-ming (Francis Ng) and his wife, Sammi Mok (Athena Chu) were on the way to finalize their proceedings for separation where an armed robbery breaks out in the streets. Kwok-ming steps in to assist in hunting the criminals, but Sammi was hit by a stray bullet and was seriously injured, leading her into a coma. Several months later, Sammi awakes from her coma. Sammi's doctor, Ko Chuen (Nick Cheung) warns her to be especially careful with her body as her blood type is very rare.