Frozen World - S1.E9

Himari has a strange dream in which she meets a man named Sanetoshi, who shows her various books containing her memories. In elementary school, she formed a group called Triple-H with her best friends, Hibari and Hikari. When she argued with her mother over buying a wrong ribbon, her mother became scarred from a falling mirror, she and her friends tried to kill a koi for its blood to heal her mother. She left elementary school due to her illness whilst her friends went on to become idols. Upon waking up after vaguely recollecting a soulmate she once had, Himari hears from Ringo about Shoma's accident.