S01:É01 - S01:E01 - Episode 1
Moo-young and Kang-ho find out a strange commonality between the case and a cold case 13 years ago.
S01:É02 - S01:E02 - Episode 2
With criminal right under his nose, Kang-ho is suspended. He begins to collaborate with Moo-young.
S01:É03 - S01:E03 - Episode 3
Butterfly serial murder resumes as Min-ki escapes. Suspicious link between him and Tak Won is found.
S01:É04 - S01:E04 - Episode 4
Kang-ho is expelled from the TF. He and Moo-young fall into a trap as Teddy and Tak's past uncovers.
S01:É05 - S01:E05 - Episode 5
The police declare the real culprit and calm public anger. But Kang-ho and Moo-young don't stop.
S01:É06 - S01:E06 - Episode 6
A boy is found dead after 10 years in a manhole. Ban-seok falls into a panic as Ka-eun disappears.
S01:É07 - S01:E07 - Episode 7
Ban-seok finds Ka-eun's bracelet on the body discovered in a mountain. He asks Kang-ho for help.
S01:É08 - S01:E08 - Episode 8
Ka-eun becomes the murder suspect of her boyfriend. And the children caught confess she killed him.
S01:É09 - S01:E09 - Episode 9
A medical student is found murdered at home. Moo-young finds its connection to another cold case.
S01:É10 - S01:E10 - Episode 10
Moo-young decides to accept the deal. Failing to arrest him, Kang-ho goes to find the only survivor.
S01:É11 - S01:E11 - Episode 11
The survivor is found inside the trash pile. And Moo-young exposes information learned from Ki-tae.
S01:É12 - S01:E12 - Episode 12
Despite Team Bulldog's hard work, the commissioner dismisses Kang-ho. The team jumps into the trap.