S1·E21 He Was Lit Up...

Kuriko tries to return her share of Kazuki's ashes to him, but she fails everytime. Then her older sister informed her that she will leave for New York, but not before she attends her family's Cinderella Party, in which the party ends at midnight. Kuriko decided to bring Kazuki along as her "man". As time passed, however, she wasn't able to restore Kazuki's ashes to him and ended up losing a shoe after running up toward the balcony when Kazuki found her standing on the stairs in hesitation of what to do. Kuriko confessed her love for Kazuki and said that this is the last time she will ever see him and they kissed... almost, as then Kuriko's ashes finally passed on into Kazuki, making him a step closer to being human again. Next day, it's seen that Kuriko somehow cancelled her journey to NY and stayed with Kazuki.