Having retreated into the fallout shelter with seconds to spare before the nuclear missiles cascaded down upon his home, Kousei Arima is the last surviving person on Earth...or is he? When he's rescued by Black Widow and an Ultron drone with the voice of Dr. Arnim Zola, Kousei is grateful. When he is chosen by The Watcher and Strange Supreme for a special mission...Kousei is scared

After The Watcher and Doctor Strange Supreme select Kousei Arima for a mission where he must use his piano playing to bring about peace in a doomed Attack On Titan timeline, Arima is placed in an alternate universe where it was not Kaori that died...but HIM. Kousei and Kaori are overjoyed at being together again. Will their love triumph over the adversity they face soon after?