Yuto has been plagued by the disappearance of his sister after he witnessed her vanish through a strange portal. Seven years later, he sees two girls emerge from the same...

Hoping to find his missing sister, Yuuto opened a mysterious door and entered the forbidden world of the other side. But Yuuto’s well-meaning action caused another girl’s death. Tormented by...

Yuuto opened the forbidden door in search of his missing older sister, Manami, but his actions inadvertently led to Hina’s death. Now, Yuuto and the girls are looking for a...

Yuuto continues to search for Manami, his sister who disappeared years ago. Along the way, Yuuto makes a shocking discovery about his own origins that only raises more questions. The...