Nanaka 6/17

Seventeen-year-old Nanaka Kirisato is a high school student who takes her studies and her goals in life seriously. She often criticizes her best friend, Nenji Nagihara, for being a childish delinquent who spends his time fighting other boys. Then one day, after a heated argument with Nenji, she falls down a flight of stairs and suffers a brain injury, which leaves her mind reverted to that of a six-year-old. Because of this, Nanaka's father and Nenji must keep her injury a secret as she struggles to live a normal life and grow up all over again.