This drama is exceptionally good! The story is remarkable. There are two sons, two fathers and two mothers. The relationships between the characters are so complicated! The revolutionary idea of this drama is that love is stronger than blood ties.
The acting is incredibly good. Everyone gives a very good performance, maybe with the exception of sister and widow. Anyway, Jo Yoon Hee (Woo A Mi, the widow, supposed main lead) have no chemistry with Kim Jae Won (detective Ha) at all and she was left aside by the director and plays a really minor role. And it was a brilliant decision.
While noona (Jang Joo Ha played by Kim Gyu Ri) has a great chemistry with everyone.

This is a classic Korean drama, in the sense that it is a story of revenge, guilt and redemption and the fight against destiny, with a bit of humor. The end is very good. Filming, direction, cinematography and music are excellent.

Drama has a serious meaning, plot twists don't leave the viewer indifferent, you just need to know what will happen next and who will be the son.

Drama is for everyone who likes a good script, real, intelligent characters, serious questions and mature music – who tastes just a good drama. Then, just watch it!