Season 1

Jo Tae-sik inspects an apparent suicide. After learning that Kim Seung-cheol died in a car accident, Kim Seo-hui can’t get a hold of Jeong Sang-hun.

Tae-sik and his team look into Sang-hun's disappearance -- and learn he and Seung-cheol were working on something together.

When a factory worker he'd been trying to find turns up dead, Tae-sik investigates. Seo-hui forces herself through a tough campaign trail.

Another grisly package surfaces. Tae-sik and his team suspect In Dong-gu is involved. Seo-hui tries to understand a bill that her party wants passed.

Suspecting something is amiss at the mental hospital, the cops send Jeon Ho-gyu undercover. Seo-hui eavesdrops on Hong Min-guk and Dong-gu.

Tae-sik untangles the mystery of the mental hospital -- but Sang-hun remains missing. Seo-hui confronts Jeong Yeong-mun about what he knew.

The search for answers continues as the police turn their attention to Jin Yeong-min, who turns out to have a long history with Sang-hun.

Seo-hui comes clean to Tae-sik about the mysterious messages she's been hiding, and probes into a funeral Sang-hun attended before he vanished.

While Tae-sik's reinvestigation into Choe Su-hyeon's death ruffles feathers left and right, Seo-hui asks around about her connection to Sang-hun.

Ignoring his suspension, Tae-sik chases leads from the list in the USB drive with Seo-hui. Kang Jin-gyeong brings Ho-gyu the dead laptop.

Tae-sik recovers the list while on the run from authorities. Meanwhile, Jin-gyeong gets to the bottom of who framed him.

Tae-sik and Jin-gyeong channel their grief into helping Seo-hui, who discovers a startling truth about what connects the people on the list.

Getting their hands on damning evidence allows Tae-sik and Jin-gyeong to set a trap. Seo-hui receives another message.

Trying to turn votes against the bill, Seo-hui holds a press conference. Tae-sik tails Yeong-min, who has his own plans for the future of JQ Group.

If Seo-hui wants to save Sang-hun, she must find one last crucial piece of evidence among her father's things. Yeong-min delivers an ultimatum.

Yeong-min and Dong-gu have a final face-to-face. A heartbreaking letter from Sang-hun is difficult to swallow for Seo-hui, but doubly so for Yeong-mun.