Hi welcome,
I am not that active on the forum, but I watch the show everyday. So Saanchi wanted to get educated and become a independant career woman. It was her and her father's dream for her to study in the university that she studies in now. This university unfortunately was not what she had expected it to be. She had to face Indu Singh and Prabal who were student leaders cum ruffians. Indu Singh however fell in love with her the first time he saw her, he used gawaar type nuske to patao her, but she thought that they were just friendly gestures. Both Indu and Prabal were trying to get Saanchi on their side as she was a topper and would attract others to their side. Prabal used Mehek, Saanchi's friend by pretending to be in love with her. Mehek considered Indu to be the wrong one and encouraged Saanchi to befriend Prabal because he is an honest man. So after Indu attacks Prabal and a bunch of stuff happens betweem them, Indu proposes Saanchi but she doesn't accept. Indu is so crazy in her love that he uses force to get Saanchi to agree, and it works. But Saanchi manipulates Indu and gets out of the shaadi fiasco smartly a couple of times. The last time she and her parents pretend that Saanchi's mother committed suicide and they send Indu to jail with Veena's false suicide note. Indu finds out and after his lawyer mama bails him, he kidnaps Tarachand and forces Saachi to marry him or he will kill her father. So they get married but Indu doesn't accept her and vows to make her shed tears all her life. Amidst this Indu's mama is Saachi's family's arch rival, he has taken away their home, now Saachi has gotten it back by hook or by crook.
The cast basically Indu's gang and Mehek are important, Roop and her brother love Indu and Saachi, and their mother the maha gossip queen. Indu's mama mami, Saachi's parents.
Hope that answered your questions.