Princess Connect: Reverse Record - Requiem of the Lost Smile

This is the story of reclaiming the smile of a precious person lost on that day. "We meet again, everyone." Yuuki smiled as he said it—and then the girl vanished before his eyes. —From that day, the world ended. Black miasma covered the Astrum Continent. Calamitous light overflowed from the Tower of Covenant. One by one, his companions fell. Pecorine smiled to the very end. "Yuuki-kun, see you later," she said. Kokkoro kept praying through her tears. "Please protect Master," she pleaded.