When a police officer is killed in the line of duty, his soul enters into the body of a young officer to seek revenge for his murder. However, when the spirit takes over, the officer is unaware of what is going on and most think he is in need of a psychiatrist, including the wife of the fallen cop.

强尼是波士顿着名的私家侦探，某次渡假到洛杉矶探视其哥哥，不料匪徒竟公然闯入将其哥哥和大嫂杀死，为了逮捕凶手他做了地毯式的侦探，并得到街头青少年的鼎力帮助，最后发现了绑匪集团的巢穴。