Breaking the Last Rule BTLR

Do not fall in love. That is the last rule in their agreement — Nelly and an exchange student, Cyrus, that is more likely next to impossible for they are fond of annoying each other. Not until when the guy saved her from getting bruises from her ex-boyfriend, everything had changed. Neither did they just become friends, but they became partner-in-crime, as well.

From how they were playfully turning the fire alarm on during their midterm exam, switching the lights on and off at the school corridor from where their most hated teacher walks by, telling that they were sick just to go to their awaited grand opening of their new favorite place, and exchanging every student's clothes in the dormitory's shower room, in the middle of the night . . . indeed, they have common things to do in mischief.

But when the day had come, when Cyrus took a chance to finally convey his feelings out loud, fear was the first thing that Nelly felt and reminded him once about the rules. But then again, is it possible that Nelly feels the same way?

Is Cyrus being the only one breaking the last rule?