Autumn at St. Michael's. The uniform shift from summer to winter brings Risa a wave of nostalgia. She and Miya are a couple now—living together in Risa's apartment—but Risa remembers when looking at Miya meant the start of an argument, and the memory makes her laugh. It started on Risa's very first day at the school, when she was just trying to get a chronically truant girl to come to class. That girl was Miya. That spring day, with sakura petals falling, is where this story begins.