Samuel and Katerina were childhood friends, He had always protected her and loves her as a friend even though she had turned out to be a rich spoiled beautiful woman. Sam had to enjoy the moment by having sex with her when she mistakenly trapped herself in a bondage bench, exposing herself. Sam then captured the moment and realized how beautiful and attractive his childhood friend had become. He had sex with her and that moment trapped her imagination as she didn't enjoy regular sex with any other person but him. She had a fight with him but couldn't continue because she realized no one could satisfy her the way Sam did. She does not apologize for anything no matter what. But she was willing to apologize and do whatever he wanted so she could feel the same way with him again.
She then found a way to apologize but Sam thought it could be a lure. Because he had never seen her that way before. When he was fully convinced that she's plain then they continued their relationship but this time stronger up to the extent that her Dad knew about it and sam's other childhood friends.
They started dating and moved on with their ever springing love.