An Intruder?

--

THUD!

"...?" Mitsuru looked around for the source of the sound, holding his sister close behind him, along with the book. Its weight was slightly heavier than before for some unknown reasons.

THUD!

"Uh... What is that...?" the two backed up until their backs were against the bookshelves. Their backs were glued to the shelves behind them, slight fear crawling up their skins as the two siblings scanned their surroundings.

THUD!!

The sound was getting louder and louder every second that had passed and it sounded like it was going towards the two siblings.

"Shizuka, get behind me," Mitsuru firmly ordered, his spells ready to be activated at any time.

THUD!!!