In the darkness of night a dangerous mentally disturbed man called Karan (Rishi Kapoor escapes from the mental asylum and this news spread in the city. Karan enters into the house of a girl called Sapna (Sridevi) who is a psychiatrist by profession. When Karan sees Sapna he becomes violent and furious and tries to kill her but Sapna makes him tame and informs the Police. Suryakant Verma, the I.G. of Police on receiving the phone call comes to Sapna's house and takes away Karan. The I.G. calls up Sapna next day and requests her to come to his house. When Sapna visits I.G.'s house and after seeing her photographs in I.G.'s house she gets flabbergasted and surprised. She enquires about her photograph. I.G. informs that the photograph belongs to some other girl called Madhu who looks exactly like Sapna. Madhu was in love with Karan and she ditched him and married some other rich man and gone abroad. Karan could not bear this shock and he becomes a lunatic. I.G. says Karan is his son and after seeing her Karan has started behaving like a normal person. He request her to treat Karan and bring him to normalcy since she is a psychiatrist.
Sapna starts the treatment and takes Karan to the places where he has shared his pleasure with the other girl Madhu so that he could easily remember his past. Karan's condition improves and finally he becomes absolutely alright like a normal person. Suryakant Verma is very happy. He appreciates and congratulate Sapna for her courageous steps and announces the engagement of Karan with Sapna. But Sapna leaves the engagement party midway and takes Karan to a lake. Sapna says she could not marry Karan because she hiding some secret and wants to disclose it to Karan.
Sapna confidentally narrates the secret hoping that Karan will forgive her but when Karan comes to know the truth he handcuffs Sapna. Sapna is shocked to know that Karan is a C.B.I. Officer. Sapna is brought into the court for the charges of murder. During the trial of Sapna in the court lot of secrets come into light.
What are the secrets Sapna reveals in the court?
Who is the real culprit or murderer?
Whether Sapna is innocent? Who is the other girl?
For answers of all these see Kaun Sachcha Kaun Jhootha on the screen.
[From the official press booklet]