Kujo Rina, homeroom teacher of Class D, Year 3, spent a year making the right decisions as a teacher with no sentimental feelings. Pushed by a student, she falls from the upper floor and time travels to her classroom one year ago.
Resolved to change her classroom so all the students graduate happily, and so she herself isn't killed, Kujo Rina does everything to support a student being mistreated at school and a student suffering from his parents' debt.
A death threat against Kujo is written on the blackboard, causing an uproar at school. The students suspect Sagara, but he denies it. Unable to stay at school, Kujo declares that she will rely on Ugumori as a trusted ally.
After Kujo's husband Ren retracts his divorce proposal, she confesses that this is her second week of life. Ugumori deepens her friendships, irritating Nishino. Kujo warns Enami about a situation from her first life involving Hamaoka.
Kujo appoints Mizuna to be in charge of an event at the school festival, surprising her, because she didn't intend to participate in the first place. Mizuna tries to refuse the role, but Kujo tells her only Mizuna can save the festival.
Kochiya confesses to Ugumori. Ugumori tries to respond, but Kochiya runs away. Kujo visits Kochiya after she requests a leave of absence. Ugumori reflects on why she was given a second life and realizes all her wishes have been fulfilled.
Hourai High School is closed after a tragedy. Kujo, heartbroken, blames herself for being unable to change fate. After meeting the student's mother at the funeral and getting support from Ren, she lifts her head and faces her class.
Kujo and her class hold a school press conference, and their sincerity reaches Ugumori Miyuki's heart. In the classroom, the students corner a classmate. Hamaoka reveals his connection to Sagara, and Sagara shocks the class.
On the day of the Ugumori incident, Sakoda and his friends questioned Hamaoka, who said someone asked him to be there. Class 3-D races to find someone, fearful that the culprit, tormented by guilt, might choose the worst possible ending.
