Nozomu notices a few members of the class playing a "spot the differences" game. Nozomu tells them that it is important to spot mistakes and he instructs the class in how life is filled with mistakes. He asks the class to identify mistakes in their lives after pointing out several of his own. After Nozomu contradicts himself, saying that a mistake was the correct action, Kafuka reasons that if a mistake comes to light, it is correct, resulting in many people approaching her, confessing their mistakes, making them correct. In the end of the first part, a boy approaches Nozomu, calling him "Dad." The second part of the episode reveals that he is actually Nozomu's brother's child, Majiru. Nozomu asks him to prove that he is indeed his nephew, and then asks all of his students to prove that they are the real one. When Majiru asks Nozomu to prove he is genuine, Nozomu is unable to come up with a response, and runs off. The episode ends with a sequence that deals with Majiru's hair fetish.

The girls are watching a particularly awful movie. Outside, they meet with the director, who defends himself by saying that he is just "following the original story." Chasing him, they arrive at roads that are used by many people to escape or to shift blame from their mistakes. In the second part, Nozomu, Majiru, and Matoi are sitting in a kotatsu in Nozomu's house. Chiri then arrives to clean up everything. After the cleaning, Nozomu keeps wishing that humans can hibernate and finally he and the regular cast decide to take a winter hibernation. However, after the group nearly dies of carbon monoxide poisoning, Nozomu decides to simply leave. Fūra goes to find him, only to witness him being struck by a runaway trolley. The episode ends at the hospital as the entire class waits for Nozomu to leave surgery.