Y/N

Y/N (pronounced as "Yes No") is a drama anime and light novel series conceived by Ryan Nurse and Animatron Studios. First conceived in July 2012 during Nurse's hospitalization, it was publicly revealed in December 2012 and began production as part of Project 20:15. It is notable for its experimental nature in which the narrative switches back and forth between two parallel timelines, the divergence point of which is a single "yes-or-no" question asked at the very start of the series. Nurse has described it as an "examination of the butterfly effect".

Y/N follows two high-school girls, Kiyomi Hanabishi and Yuuko Sakuraba. In the "Y" timeline, Kiyomi skips school with Yuuko and saves her from being hit by a car, but is run over and killed in the process; in the "N" timeline, Kiyomi goes to school instead and Yuuko is hit and killed. Each timeline deals with the surviving girl's feelings of guilt, loss and anger, as well as the reactions of those around them such as their friends and family - as well as the driver responsible.

Characters

 * Kiyomi Hanabishi: In the "Y" timeline, she is killed while saving Yuuko's life. In the "N" timeline, she instead blames herself for Yuuko's death.
 * Yuuko Sakuraba: In the "N" timeline, she is run over and killed. In the "Y" timeline, she is extremely upset by Kiyomi's death and swears vengeance on the driver.
 * Junko Kirishima: A woman who comes across the dying Yuuko in the "N" timeline, and the scene of Kiyomi's death in the "Y" timeline; in both timelines she is shaken by the events.
 * The Driver: The (currently unnamed) unnamed man who hits either Kiyomi in the "Y" timeline - in which he is arrested - or Yuuko in the "N" timeline - in which he flees the scene.