Beyond the secret (1-4 volume latest edition)

Publisher: KADOKAWA/Kadokawa Bookstore
Author: Hidoro Yoshikawa
Size: 128mm x 182mm
Number of books: 4
Language: Japanese
Category: Youth manga, manga
Latest release date: 2015-11-21

Synopsis:
After school, enjoy a conversation with friends without love. Yuto, a boy who is living such a common student life, had a problem that people could not speak. Seven years ago, Manami, my sister, said with a mysterious door, "It has disappeared. Yuto continues to search for her sister's whereabouts, relying on the door left in the memory, but I could not get one clue. At one point, a secret door of the secret that was forbidden to enter my sister suddenly appeared in front of me, and two beautiful girls jump out of the inside. And the girl has an older sister. The "secret treasure" was held. At last, I can't miss the clues of my sister I met! To know the important sister's whereabouts, Yuto steps into the forbidden world lurking behind everyday!