Snehmoy and Miyage are pen friends who exchange wedding vows through letters. Fifteen years pass but they never meet. Yet the bond of marriage is strong between them. This unusual relationship comes under a cloud when a young widow, Sandhya, comes to stay with Snehmoy along with her eight-year-old son Poltu. Snehmoy and the little boy bond and the arithmetic teacher discovers the joy of palpable bonds and fatherhood. There develops an inexplicable thread of understanding with Sandhya too. But Snehmoy remained loyal to his unseen Japanese wife.
