Saeki's Cosmetic Surgery Clinic is a clinic owned by Shinichi Saeki, who works as a cleaner for the underground. Though he is a skilled cosmetic surgeon and takes his profession seriously, Saeki also uses his clinic as a front for his side business of procuring, disposing of, and altering corpses. The clinic is often visited by other members of the Hakata Tonkotsu Ramens baseball team needing their wounds dressed, surgery performed, or looking to buy corpses or body parts.
The clinic is described as snug and small. During daytime hours, nurses and patients are around the clinic, but only Saeki is present in the evenings, handling bodies in a secret examination room in the back. In the first story arc, the bulletin board in the waiting room has a poster for the Hakata Tonkotsu Ramens grasslot baseball team, which is in need of both a pitcher and a shortstop.
Mayor Harada Scandal Arc
After Xianming Lin's fight with Hisashi Ivanov, Zenji Banba brings him to the clinic to have his stab wounds treated by Saeki. Later that day, Jiro Tanaka visits to dispose of the body of Shota Yamazaki. Shortly after learning of the price the Kakyuu Association has placed on his head, Banba returns to the clinic and offers to buy the boy's body, intending to play dead. Upon seeing Jiro, he requests that the avenger take revenge on the mayor's son for the rape and murder of Qiaomei Lin.
Later, Jiro gives Kazuki Saitoh Saeki's business card, and Saitoh has cosmetic surgery performed, allowing him to distance himself from both Murder, Inc. and the national news bulletin that had pinned him as a murderer. Deciding on a new start, Saitoh calls Jiro and informs him that he would join the baseball team.
Niwaka Samurai Impersonator Arc
When José Martínez is hired by Abe and Yamamoto to torture information out of Lin, Saeki hurriedly prepares a double for Lin with a corpse of a young man. When the torture and switch are complete, Martínez brings Lin to Saeki's clinic, where the doctor dresses Lin's wounds, gives him painkillers, and allows him to get some sleep. Saeki greets him when he wakes up in the morning and answers a panicked call from Genzo Gohda, who after seeing the mutilated corpse resembling Lin, has been looking for Banba in a panic. The two exchange stories, and when Lin learns that Banba has gone to retrieve his body from the Submarine Ninja, he rings Enokida, hoping to keep Banba out of danger.
Shou Wang Arc
After the events of the story, Saeki stays late at work before going to attend a fireworks festival with the rest of the Tonkotsu Nine.
Over the course of six months, the clinic has been receiving badly beaten corpses of mostly homeless men via courier, and Saeki becomes unnerved by the condition of the bodies and anonymity of the sender. Through Genzo, he hires Lin with finding and eliminating the culprit. The next day, Saeki receives the body of Manabu Kuroiwa with his personal possessions included. Lin visits the clinic to examine the body and gather clues that could lead him to the killer.
After Jiro is shot in the arm by members of the Mutagawa Group, he visits the clinic, where Saeki removes the bullet, gives him stiches, and puts him arm in a sling. The doctor invites him to sleep in the examination room overnight, and despite Jiro's disgust at sleeping next to the corpse on the other bed, he collapses as soon as he tries to stand. Saeki stays in the clinic, working on the corpse until Jiro wakes the following afternoon.