The Unwanted Graduate(1979)

After her husband is killed in an accident at work, Noi has to find a job in order to raise her two daughters who are still teenagers, Val and Vanee. Val has a boyfriend named Ratch, but she has to sell herself to Uttasit in exchange for money to pay her mother’s hospital bills. Uttasit wants more of Val so he goes to look for Val, but he finds Vanee instead. Vanee is pregnant because of Uttasit and dies from abortion. Val wants to kill Uttasit, but before she can do anything, Noi breaks in and shoots down Uttasit and surrenders to the police. Later, Noi and Val find out that Ratch actually is Uttasit’s son.