Guna (Kamal Haasan) is a mentally affected person and receives treatment in a mental hospital in Hyderabad, India. He does not like his father, and his mother Manonmani (S. Varalakshmi) is a moll in the house that they live. He assumes a fictitious character named Abirami (also the name of an Indian goddess) and registers in his mind that she is an angel who is going to marry him on a "full moon day". After coming out of the asylum, he believes the story to be true and believes that his Abirami is somewhere around.