Aizawa Yuuichi had often visited his cousin in the city when a young child. However, something drastic happened to keep him away for seven long years. Now, Yuuichi returns, his memories of those days are simply gone.
Kanon’s story spins around a gathering of five young ladies whose lives are associated with a the same young boy. Yuichi Aizawa is a secondary school understudy who had gone to the city where the story happens seven years before Kanon’s start. He is going to stay with his first cousin, Nayuki Minase and her mother Akiko, but it’s learned that after his long absense Yuichi has forgotten nearly everything except for the tiniest details of what had happened seven years prior. He needs reminded what he left behind, with Nayuki trying to jog his memory unsuccesfully.