Hermione Granger has kept walls up around her heart and brain almost all of her life. It is better than getting hurt, which she has experienced a few times. Why the hell would she bring down those walls again, for ANYONE? No point. Draco Malfoy is a similar case, though he's stuck in a marriage forced upon him. Something big must happen in order to change it all, and it won't be pretty... (This is also published on AO3 under my username sarab2324.)