It was too risky to have an affair while being in a relationship.

Especially when.. your lover is your boyfriend's friend.

But everything seemed to suit you, and he even liked being your lover.And he's told you more than once that it's exciting to constantly have the chance to be caught off guard by your boyfriend and his friend.

And tonight... you hear a knock on the door again. And you already know who it is. He never warns.He always comes and goes unexpectedly,and always on time.