Yeh Kaisa Farz (1985)

After death of her husband Sumitra Devi raises her son Deepak as single mother who goes on to become a police inspector and criminals fear him.Tara his childhood friend loves him secretly but Deepak falls in love with Pooja daughter of wealthy Din Dayal and both get married soon.After their marriage things are not the same as Sumitra and Pooja have frequent fights and Deepak whose working on a high profile case of Rawat Singh is distressed.Deepak has to travel to Benaras to find details of Rawat Singh but upon returning he gets the shock that Pooja has be killed and suspicion leads to Sumitra Devi.Deepak finds all the evidence against his mother and has no option rather then to arrest her.