Dastaan is a page torn from life's storybook, whose author is Fate. Anil (Dilip Kumar) and Sunil ( Dilip Kumar) are twin brothers who are the childhood friends of Meena (Sharmila Tagore). An ugly twist of fate separates Sunil from the rest at a fair where they had gone together. Sunil is given up as dead but Meena still believes he's alive and awaits his return. Sunil has lost not his life but his memory and grows up in a small town where he becomes a sessions judge. Sunil now Vishnu Sahay is also a married man, his present life complete and happy, peopled by his wife and his friends. His past is a complete blackout that for him never existed. Will fate relent? Will it reward Meena's faith by letting her meet her beloved Sunil? If so, what about his other life? Will the path of true love and devotion finally make it's way over the horizon of happily ever after? If so, how?