She looks happy on the outside, but on the inside she's puzzled about how she really feels.

Does she love him? Or is she just putting up an act to make it look like she's forgotten her past?

What happens when he suddenly tells her that things are over between them?

He seems to be the kind of guy that doesn't really care much, but really he's head over heels for her.  

One careless mistake causes him to do something he regrets deeply, but if he loves her, he should let her go, right?

What will become of these two?