Kyoukai No Kanata: After-Story

A year has pass since Akihito Kanbara and Mirai Kuriyama reunite and retrieved her lost memories. They would both try to improve their relationship. Then one day a mysterious girl with braided black hair, and has glasses appears out of nowhere. Akihito found the girl attractive, especially in those glasses. Mirai would want to try her best to get to know the mysterious girl, and her dark history. Beyond the Boundary is what the girl seeks only.

Cover image by Miin敏 (via Pixiv):
https://www.pixiv.net/en/users/4335725