Jasper Railsback is a pediatric surgeon in Cataract City, by Niagara Falls. In the NICU, he does brain surgery on an infant with a foreign mass in her brain. His left hand is his dexterous one; his right arm, the brawny one. It is as though Jasper's body is divided in two — the right side extremely muscular and well-proportioned, and the left skin and bone, functional but devastated in comparison to his other side. At the Ontario Arm Wrestling Association's Arm Melter event, Jasper wins against his opponent, and breaks his opponent's arm in the process. His success in wrestling is attributed to his technique and his impressive right arm. In Youth Services Court, Jasper testifies for the Child Services agency about a little boy whom he operated on. The boy was delivered prematurely as a result of his mother's meth use, and Jasper argues he should be separated from this mother. Jasper shows the court his own arms — Jasper's mother was an alcoholic, causing his severe bodily disfiguration. Penny, the Children's Aid Society worker present at the court, thanks Jasper for testifying. That night, she comes over to Jasper's apartment.
In his apartment, Jasper leaves Penny sleeping in his bed in order to medicate with synthetic testosterone — which prevents him from developing breast tissue. He thinks about how many bullies he dealt with as a child, how they eventually learned to stop messing with him because he wasn't an easy target. Penny finds him in the kitchen and they chat. Pointing at her swollen belly, she reminds him that her baby could be his. He tells her it's not possible because his testosterone levels are so low. She tells him that it only takes one viable sperm, and he reminds her that the baby is most likely her husband's. Jasper is defeated at the Arm War Classic Finals. He heads over to a strip club, where a female stripper brings him back to her motel room. They are about to have sex when the stripper's son bursts into the room from an adjoining room, asking for water. Jasper can tell the child has Cystic Fibrosis, and he shows the child his own mis-shaped torso and teaches him how to arm-wrestle. He leaves the motel without sleeping with the woman, and heads straight to the hospital; he's been called in. In the operating room, Jasper works to save Penny's premature child. He notices the slope of the child's nose and remembers Penny's words — it only takes one. He operates feverishly, thinking only of his son, his child.