Like Father, Like Son

Ryōta Nonomiya is a successful architect who is focused so much on work that he neglects his wife, Midori, and son, Keita. Upon his return home one day, Midori tells him that the hospital where Keita was born urgently needs to speak to them, and Ryōta senses trouble. After arriving at the hospital, the couple learn that their biological son Ryūsei was switched with Keita at birth, and after DNA tests prove the error, they must now make a life-changing decision to either keep Keita, the boy they raised as their own son, or exchange him for their biological son. Ryōta and Midori soon meet with the other couple, Yukari and Yūdai Saiki, small-town folks who lack the money and drive that Ryōta possesses, but who have a better understanding of the importance of child and parent bonds. They share photos, and for the first time, Ryōta and Midori see their biological son, Ryūsei. After several meetings, they decide to exchange children for one Saturday. As the Saiki family has two other children, Ryōta suggests that he and Midori permanently take both boys, offending the other couple. Both couples sue the hospital responsible for the mistake. During court proceedings, a nurse admits that she deliberately switched the babies; as a newlywed struggling to raise her stepchildren, she grew envious of the Nonomiyas' happiness and spitefully switched the children. Because the statute of limitations has expired, she cannot be charged for the crime. After several more meetings, they finally decide to exchange children permanently. All four parents have difficulty accepting the loss of their previous sons, and the absence of the parents they used to know causes both boys to shut down emotionally, culminating in Ryūsei running away from the Nonomiyas' home and returning to the Saikis'. Ryōta picks up Ryūsei and brings him back home. The Nonomiyas receive their share of the payout from the lawsuit, plus additional money from the nurse as an apology. Ryōta goes to the nurse's apartment to return the money and berate her for ruining his family, prompting her stepson to intervene to defend her. Ryōta and Midori begin to bond with Ryūsei, who is also warming up to them. However, while going through the photos on his camera, Ryōta discovers a cache of photos of himself, mostly sleeping, that Keita took, and he breaks down crying. Ryōta and Midori visit the Saiki family with Ryūsei, but Keita runs away from Ryōta. While following him, Ryōta apologizes to Keita for his failures as a father, and the two make amends. The film ends with the two returning to the Saikis', and both families entering the home.