Shweta (real name Preeti) is murdered. She was younger among her elder sister Tanuja (real name Neha and played by Simran Khanna). She died of drowning in water in her bathroom's small tub. Her mother and brother-in-law raises complain that she was killed by his father Anand Pal (real name Bhim Singh and played by Pankaj Berry), who is a archaeologist. Shweta was in love with Hussain (real name Saqib and played by Sandit Tiwari) and their relation was not accepted by her father. Anand was also not in favour of his elder daughter Tanuja who also did love marriage and after the marriage couple was living at Anand's home.
On the other hand Anand is saying that he did not kill his daughter and this all is conspiracy of his wife (real name Shashi), daughter Tanuja and son-in-law.
Here is the inside story of the case: