Obsessive Master and Cunning Servant

Years ago, a piano teacher robbed a wealthy family, leaving the father dead and the mother broken, and their orphaned heir has spent two decades nursing a grudge. Now grown, he returns and plans to use her son as a tool for revenge, but his scheme begins to unravel as love and hatred tangle together. When he jails the teacher and disappears, five years pass and the son rises to become a ruthless CEO who eventually cages the heir himself.