Neela (Sharmila Tagore) and Avinash (Rajesh Khanna) are medical students.They fall in love with each other. However, Avinash realises that he has blood cancer. He tells Neela that she should live her life and not die with him. Neela goes to teach a young boy called Monto whose elder brother Shekar kapoor (Feroze Khan), instantly falls in love with her. Avinash convinces Neela to marry Shekhar but does not attend their marriage. Neela again resumes college and goes to check on Avinash. When Shekhar comes to know, he starts suspecting that Neela and Avinash are having an affair. He asks Monto to keep an eye on them. Monto tells Neela about this and Neela and Shekar have a fight. Shekhar, who is already depressed, consumes cyanide and dies. Neela is then charged with murder. In the meanwhile, Avinash who knew that Shekhar was unhappy about his relationship with Neela, leaves town. Neela is subsequently put behind bars. Her mother in law, however, supports her and she is relieved from the murder charge. She again resumes college and goes on to become a great doctor after a few years. Monto informs Neela that Avinash is back. Dr Chandra (Ashok Kumar) who had taught both Neela and Avinash, clears Neela’s misunderatanding. Neela goes to meet Avinash, but he dies. Monto blames Neela for Avinash's death. Years later, Monto writes to her that he understands her love and secrifice, and that though he is going abroad he would always be close to her heart. Neela continues her service to mankind.