Ascendance of a Bookworm: I'll do anything to become a librarian

On the way home from Heidi's workshop, they hear the emergency bells sound through the city as well as see a red emergency flare go up into the sky. Main is worried about what might've happened. It is decided that Main should stay home until they can find out what is going on. Main gets to spend some time with her family back home again. After a while, Main is finally allowed back outside and heads to the cathedral. Once she gets there, she realizes Dirk is missing, and unbeknownst to her, there was another threat lurking just around the corner!