If you haven't watched any K-drama for the last ten years, this is a must watch. It will introduce you to almost every over-worked trope in the genre. One by one, you can tick them off - amnesia, getting hit by a truck, false identities, adoption, abandonment, unmarried pregnancies, cancer. Did anyone have Altzheimer's? I don't remember, the whole drama made me wish I could have selective Altzheimer's and forget it all.
It actually starts out well, with good characters and a nice plot. But as soon as the amnesia hits, it becomes absurd and labored. Did they change writers mid stream? Was there a crisis in the writer's life? It's pure garbage from then on.
The only thing I'm keeping from this drama is the lovely theme song, Love Always Run Away," sung by Lim Young Woong. For the rest - I wish I could have the hours I wasted on it back. Don't start, it's good at first but fails completely later.