"Play Ball" is the 1st episode of the anime.
The episode starts on May 24 at midnight in Hakata, Fukuoka. Zenji Banba comes back home and notices a light in his window from the street. He opens the door and encounters Xianming Lin watching TV at his place. Lin introduces himself as a killer hired to assassinate Banba.
The next scene takes place 18 hours earlier. Lin shows up at Takashi's apartment and tricks Takashi's lover into letting him inside. He kills her with a knife and explains to Takashi that he's been hired to assassinate him by the organization that runs the club Miroir because Takashi took their money. Lin proceeds to kill Takashi.
Lin receives a call from Zhang who asks him to kill a police detective next. After ending the call, Lin reminisces about his younger sister Qiaomei from whom he's been separated as a young boy and with whom he hopes to be reunited after paying off his debt.
In the Tokyo office of Murder Inc., Saitoh says goodbye to his coworker Nguyen before being transferred to the Fukuoka branch. Saruwatari is shown arguing with a superior.
Back in Hakata, Lin goes to detective Takeda's address to kill him but learns that Takeda already committed suicide.
Banba and Shigematsu meet in a park. Shigematsu shows Banba a photo of the detective's body and tells Banba that the detective was investigating organised crime. Banba deduces that the detective was strangled. Shigematsu says that he received a letter from an anonymous sender who might have been the dead detective the previous day. It is a photo of Mayor Harada, a woman and two men taken at a club.
At the same time Mayor Harada is speaking in the park, accompanied by the same woman as in the photo. Banba establishes she is a hired killer by her reaction to popping a balloon with the sound that resembles a gunshot. He suspects she was not the person who killed the detective, though.
The woman, Reiko, gets into a car with her associates Munakata and Shinohara. Munakata informs her that another one of the mayor's hired killers, Ivanov, killed the detective, making it look like suicide. Munakata receives a call from the mayor's son, Yusuke, who asks him to take care of the body of a woman he killed.
Banba meets with Enokida at an internet cafe to find out Reiko's identity. He also learns about Ivanov, a killer who left Murder Inc. at the same time as Reiko and specialises in strangulation.
Ivanov, Reiko and Shinohara go to Yusuke's place. Ivanov and Shinohara take away the dead woman's body in a large suitcase. Reiko witnesses Yusuke watching a video of three of his friends beating up two men because he told them to do that and asks for the friends' names to take care of the matter.
One of the men who were beaten up by Yusuke's friends goes to Bar Babylon where Jiro is the manager and tells Jiro that the other man is in a coma in critical condition. Martínez and Misaki are also at the bar. The man gives Jiro a card that one of the attackers dropped at the scene and asks Jiro to avenge his friend. The name on the card is Jun Murase.
At the Fukuoka branch office of Murder Inc., Saitoh gets the assignment to assassinate Jun Murase for being a bothersome neighbor. Saitoh's boss gives him new business cards for him to use with the fake name Takuya Itou on them and warns him about the killer of killers from Hakata, the Niwaka Samurai.
Banba bumps into Yamato on the street. Yamato steals Banba's wallet but Banba catches him doing that. They go to Genzo's food cart together where Banba asks Yamato about the photo of the mayor. Yamato recognizes Takashi as one of the men in the photo and informs Banba that Takashi was killed this morning.
Lin goes to an ATM and checks the balance on his account. He realizes he's only been paid the full amount for killing Takashi, but not detective Takeda who was actually killed by Ivanov.
Banba shows Genzo the GPS-equipped redback spider model listening device he got from Enokida.
Yamato encounters Lin on the street, arguing with Zhang on the phone. He steals Lin's wallet but Lin thinks he touched him instead, punches Yamato and leaves. Yamato keeps Lin's wallet.
While buying what he needs to carry out the assassination job, Saitoh sees a poster of a baseball team looking for a pitcher and a shortstop.
Banba goes to the club Miroir and asks about the man in the photo who was there with the mayor. The worker of the club claims not to remember anything.
While Saitoh's waiting for Murase at Murase's apartment, Jiro and Misaki show up pretending to be new neighbors. When Saitoh opens the door, they kidnap him, assuming he's Murase.
Lin goes to Zhang's office to complain about not being paid for detective Takeda's death. Zhang refuses to pay him and asks him to kill Banba for sniffing around club Miroir.
Munakata complains to the mayor about Yusuke's behavior. The mayor tells Munakata to buy women for Yusuke from a human trafficking organization he knows.
Banba goes to his office where he encounters Lin watching TV. Lin tells Banba he's a killer hired to kill him. Banba attacks him but Lin stops him and tells him he came to protect him instead.
- Saruwatari makes a cameo appearance in this episode.
- Lin's smartphone, which was pink in a scene from this episode in the 2nd anime trailer (Lin's call to Zhang before he encounters Yamato), is white in the actual episode.