When she had been a little girl, her father had once told her that life was the best teacher because each lesson it taught, each test it handed out, remained etched in your mind for eternity.

It had sounded like a riddle to the nine-year-old girl, but she had never forgotten those words.

What they meant, however, she didn't know until much later.

Thirteen years later, precisely

At 22, life taught her all sorts of unforgettable lessons: good triumphed over evil, everything you needed to know could be found in books, not everything was what it seemed, what didn't kill you made you stronger, it was always darkest before the dawn, and not everyone that passed through your life was meant to stay.

But everything and anything sensible had immediately slipped her mind when Lee Donghae had decided to spend the night (just one night) with her.

And thus began a cycle of events Im Yoona should have been smart enough to avoid.