S1 • E1
Detective Yoo Ji Cheol receives a tip about a gambling parlor and is told to check the place out. He looks around the place but finds nothing suspicious and gets ready to leave.!!.
S1 • E2
While working, Seon Joo unintentionally attends the fan signing event for fighter Lee Min Woo. They seem to know each other from before, and he asks her how Ji Cheol is doing.
S1 • E3
The bus Ji Cheol is in gets into an accident and turns over, and Ji Cheol realizes that the pills from the laboratory gives him superhuman strength.
S1 • E4
After much consideration, Ji Cheol decides to fight at an illegal boxing match and contacts Kim Yong Dae of YD Promotion.
S1 • E5
Joo Gook Seong offers a big sum of money to Ji Cheol and asks him to play seven matches. In addition, he also tells him that he does not need to win every single time but just needs to attend them.
S1 • E6
Despite Seon Joo's plea, Ji Cheol decides to accept Gook Seong's offer and prepares seven pills for the matches. Young Seon finds out that her dad will be fighting again and gets frustrated.
S1 • E7
During a flashback of his match with Lee Min Woo who was a rookie back then, Ji Cheol gets a call and is offered three times his prize money if he loses the match.
S1 • E8
Sang A badmouths Ji Cheol in front of Young Seon, and they get into a fight. Ji Cheol is once again forced to face Sang A's mother. When he tells Young Seon that he will not condone her fighting, she tells him that he is a fighter himself.
S1 • E9
Young Seon decides to audition for The Ultimate Dancer alongside Sang A. After Sang A's performance, the judges are in awe.
S1 • E10
Young Seon passes the first round of the dance competition. Seon Joo finds out later on and congratulates her.
S1 • E11
The police retrieve the test subject Choi Yong Woo's body but have a difficult time identifying him due to his marred face and missing hands.
S1 • E12
Suspecting her mom is having an affair and her parents, a troubled marriage, Young Seon purposely sets up a date night for her them without Seon Joo's knowing.
S1 • E13
During a flashback of the day Ji Cheol went to the laboratory to get tested and became acquaintances with Choi Yong Woo, Yong Woo is seen sneaking into the laboratory while the workers go on a lunch break.
S1 • E14
Seon Joo wakes up late on the morning of Young Seon's next show, and she ends up arriving late. To make matters worse, Young Seon trips while dancing, and the judges fail her.
S1 • E15
Only having a few more pills left, Ji Cheol tells Gook Seong that he will retire after fighting the remaining three matches in his contract. He then asks him to book his last fight with Lee Min Woo.
S1 • E16
Ji Cheol hands Seon Joo the divorce documents and moves out of the house to the new house by himself. He tells her that he thought making money was all that mattered in order for him to support his family but that he was wrong.
S1 • E17
Ji Cheol fights against Sang Goo and makes a dramatic turn of events. However, he gets caught taking something while getting a short rest. Lee Min Woo is impressed by Ji Cheol's match, so he challenges him while Ji Cheol exits the stadium.
S1 • E18
Ji Cheol learns about the real reason why Seon Joo decided to write Min Woo's autobiography. He apologizes to her and the two clear their misunderstandings.
S1 • E19
Dr. Cha Seung Ho from Shingoo Pharmaceutical comes to visit Ji Cheol at night. Dr. Cha explains that the drugs Ji Cheol has is still in development and asks how many times he has taken the drugs.
S1 • E20
Gook Seong believes that there must be something about Ji Cheol's extraordinary strength. He visits Seon Joo to find out if she knows any secret to her husband's conditions. Sang Goo also starts to suspect Ji Cheol of taking a drug.
S1 • E21
Out of guilt, Ji Cheol decides to go against his opponent without taking the pills. However, the drug developers are keen to see Ji Cheol consume them so that he is in the right condition before any tests can be done on him.
S1 • E22
The match between Yoo Ji Cheol and Kang Sang Moon continues. Sang Moon corners Ji Cheol and keeps attacking Ji Cheol's left shoulder and arm that Ji Cheol already got injured from the previous match.
S1 • E23
Ji Cheol runs away from home because of the guilt from seriously injuring Sang Moon. Yeong Seon gets worried about him and goes out to find him.
S1 • E24
Gook Seong confesses that he's the one who slipped in the drug in Ji Cheol's water. Ji Woo tries to cover for Ji Cheol and tells Hyun Soo to stop the investigation on Ji Cheol.
S1 • E25
Ji Cheol hears that his declining performance was because of a type of amyotrophia. Gook Seong finds out that Ji Cheol is at his limit of using the drugs and prepares to set him up for a big rematch with Min Woo.
S1 • E26
Min Woo meets Ji Cheol and blames him and Gook Seong for ruining Sang Goo and Sang Moon's lives. Ji Cheol gets angry after knowing the truth about what Gook Seong has done and runs off to see him.
S1 • E27
Jin Sang Goo gets killed right in front of Ji Cheol. Dae Seong tries to hand over the evidence of Shingoo Pharmaceutical's crimes to Ji Woo, but Doctor Cha stops him to save his daughter.
S1 • E28
Jong Doo gets killed in the lockup. During Jong Doo's funeral, Pil Doo decides to take his revenge and leaves the place. Chairman Jeong gives up on his attempt to kidnap Young Seon.
S1 • E29
After hearing that Young Seon has a disease, Seon Joo is devastated and Ji Cheol is worried that her illness could be passed down from him.
S1 • E30
Young Seon's condition is getting worse. Gook Seong visits the hospital and gives money to Seon Joo for consolation, but Seon Joo refuses.
S1 • E31
Ji Cheol hands over a voice recording file of Gook Seong to the police and says he'll pay for what he has done after having a match against Min Woo. Gook Seong keeps putting pressure Ji Cheol to take the drug before the match.
S1 • E32
Ji Cheol and Min Woo fight each other with all their strength until the bell rings and even the commentators say Ji Cheol shows the best retirement match in history. Seon Joo and Young Seon watches the match on television in the hospital.
Yoo Ji-cheol
Yoo Young-sun
Kim Yong-dae
Kim Sang-ah
Park Min-shik
Choi Seon-joo
Cha Ji-woo
Gambler
Chief Park
Young Yoo Young-sun