They had only met a few days earlier and SS had told Nihal about his history. How he left home etc. Nihal had just come back from Canada. They were sitting together in a coach and Nihal left his duffel bag under his seat by accident. SS found it and returned it to Nihal. There was 30 lakhs in it. Nihal was very grateful to him.
Then when SS was at Nihal's house a documentary done on PP was on TV. They showed Ratan in it as well. Ratan said that it's time for "Those who have left to come home". SS knew she was talking to him. He told Nihal that he has to go home to his wife and family. That his wife has forgiven him. Nihal offers to give him a ride to PP.
On the way there, they have some issue with the vehicle I think. SS gets down to look at it, and then the car rolls, Nihal is at the wheel. He gets thrown off the side of a cliff. Nihal tried to save him but SS ended up letting go. He fell off the cliff. Nihal was racked with guilt and came to PP and pretended that he was an old friend of SS. He lied and said he borrowed some money from him and wanted to return it. He gave them 20 lakhs I think. Then he started to feel attached to the kids and the family. So he stayed back in PP and helped Ratan to run the farm. He soon fell in love with Ratan.
Chaiji asked Nihal to marry Ratan coz she realised he was in love with her. However, Nihal is feeling very guilty about SS and tells her he can't marry Ratan. Chaiji had found out about Nihal's part in SS death and she eventually accepts that it was an accident. So she was ok with Ratan and Nihal getting married. Bansuri finds out about Nihal and SS. Bansuri had a thing for Nihal and he didn't return her feelings. She was very jealous of Ratan coz she knew Nihal loved her. She goes and tells Balwant that Nihal killed SS. The rest of the village find out and they try to kick Nihal out of the Pind. They actually try to beat him up and kill him. But Ratan stops them. Nihal agrees to leave the Pind.
Ranvi finds out what happened and accuses Nihal of killing SS. He acts like a psycho and would not let it go. He even says he is going to look for Nihal and get revenge, when he finds out he has left town. But finally Ratan convinces him to let it go. She tries to explain to him that it was an accident, but Ranvi remains adamant. Nihal never contacts the family again and until Veera met him in Poland no one even knew where he was. That was around 15 years ago.
So that is the long and the short of it. I only started watching Veera after Nihal came it the Pind. Never saw it before that. Even that I started to watch half way. Around the time when Ranvi goes to Amritsar looking for SS.
Hope this helped! :)