Mad Dog

Choi Kang-woo, an ex-detective, forms his own investigation team after losing his family in a fatal plane crash; Kang-woo encounters Min-joon while investigating a fraud case.

Kang Woo's team investigates on an insurance fraud case that involves a man named Ko Jin Chul; while chasing him down, Kang Woo misses his flight to Jeju Island that he planned to go with his family; the plane carrying Kang Woo's family crashes.

Min Joon threatens Kang Woo to get what he wants with a clip that contains all the illegal deeds Kang Woo committed while investigating cases; Kang Woo secretly goes into Min Joon's house, where he finds the articles related to the plane accident.

Kang Woo finds out that Min Joon is after Lee Mi Ran who made Bum Joon take out eight different insurance policies before the plane accident; Kang Woo helps Min Joon by chasing Lee Soo Oh to find out why Kim Min Joon is after Lee Mi Ran.

Both Kang Woo and Min Joon go after Lee Mi Ran who is still alive; Min Joon steals Cheetah's phone to get information; he finds Lee Mi Ran before Kang Woo does.

Kang Woo doesn't understand why Ko Jin Chul killed Lee Mi Ran and why he had to hurt Min Joon; Mad Dog members set a plan to catch Ko Jin Chul; Min Joon moves on his own after he wakes up from the hospital.