OK, first of all, what part of the chapter are at, exactly?
Since you mentioned the library, I assume you're right after leaving Jeanne in Cindy's care, and Lianna reads the part of her master's letter that mentions the place. As it's already too late, Lianna goes to sleep and, on the following day, decides to check on Jeanne before heading to the library. If I got where you are right, that means you just have to go to Cindy's house again.
I'll add a scene where, if you try entering the library at this point, Lianna says "I should go to Cindy's house see how Jeanne is first" in case anyone else makes this understandable mistake. Sorry for the confusion!