Tairitsu was once a normal girl with a cheerful personality, but following multiple attacks by the Arcaea imbued with conflict, she is overcome with despair and turmoil. She slowly sees the world of Arcaea as a dark, twisted world only filled with memories full of conflict. She looks at those memories with hysteric pleasure. Even so, she still hopes that one day, she will find a memory that glows with light and happiness.

Arcaea
Arcaea are melodical shards of the past that call out to the girls, but each chooses to be experienced only by one or the other. Over time, the girls begin to notice inconsistencies in the Arcaea that choose them and develop conflicting views about the world as it once was.