Hi, I've actually only started watching this lakorn, and on ep. 3, so I can only tell you what I've seen so far. N'ek and p'ek have both experience injustice by the second n'ek's father. Second n'ek's father killed p'ek's parents because he wanted the land that belong to them. Her father also took his sister to be his mistress. N'ek is also in a similar position except that she and her brother were accused of killing her father. I think her stepmom aid in this situation, and thus they lost all of their inheritance including the house.
P'ek comes back to get revenge but his sister doesn't seem like she wants to anymore? N'ek and her brother formed a gang and also wants to get back at second n'ek's father. The second p'ek is just police officer, trying to bring justice to everything. However, he thinks p'ek and n'ek are also bad guys, so he also goes against them. Second n'ek is unaware of the bad things her father has done, and thinks that he's a good person.
This is what I know so far lol, hopefully, it helps.