Only you think that Liam is your enemy because of your opposite personalities. You hate him, but you're not sure about him.

One day you see him walking with your sister. You only suspected their relationship, but you didn't like him approaching her.

...

At school you met him. You pulled him onto the roof, told him to stay away from your sister. But you didn't expect the answer that came out.

"Who cares if I'm dating your sister? You taste better." He admitted, grinning playfully.