do you mean you can't get the book from her? if so you just need to talk to her in the library and she will give it to you it can only trigger if both her and ruby are there so if she is your girlfriend already it will be harder to trigger then talk to the librarian to start the next task
Carol isn't my girlfrind yet, because idk how to pass from the 4th date.
And yes I never see Carol and Ruby toguether, every time I go to the Library she is alone.
Tell me what are the steps to get the book? I need to talk with Ruby? What do you do trigger the event? Did you activate the Elena's quest before Carol's quest? if yes, What did you do to trigger the event? if no, What are the steps that I need to follow?
It's really necesary to do the Master's checkout quest, like say the walkthrought?
Edit:
I do it, finally I do it.