Kingyo no Ubugoe

"If your memory returns, I can no longer be with you." Tomohisa and Yuta live on a small island called Sato. In the past, Yuta lost his memory and returned to a state similar to that of an infant. He was helpless. While Tomohisa, for some reason, does not want his memory to return. What is he trying to hide? (Source: MU)