Girls' Sealing Club

Story
"Merry, shall we go and see the entrance in Rendaino?"
It was two days ago that she made the proposition.
The Sealing Club, whose sole members are the two of us, is mere common club for mediums.
Yes, it's a group for mediums, but we are not into ghost summoning or exorcising as the others do.
They just believe we are an incompetent group that does not participate in the usual activities, but the truth is...