Yashovardhan Raichand (Amitabh Bachchan) and his wife Nandini (Jaya Bachchan) have raised their sons, Rahul (Shah Rukh Khan) and Rohan (Hrithik Roshan) showering them with love and affection. Yash has tried to pass on to his sons the values, heritage and traditions of their family.

Nandini has different dreams for her sons. Dreams of love that she wanted both her sons to experience, more so Rahul as she shares a special bond with him. A bond that has been cultivated with love for a child that was never meant to be... a child who was adopted. Rahul's adoption was a secret never discussed in the Raichand household. Ever since Rahul found out at the age of 8 years, it became the reason for his unending gratitude for his parents- especially his father. His father's every wish became a command for him. A command which he never breaks until he falls in love with Anjali (Kajol)- a bubbly girl from Chandni Chowk, who dotes on her younger sister Pooja (Kareen Kapoor).

Rahul marries Anjali and brings her home but his father doesn't approve of her. Rahul thus decides to leave home causing his mother's every waking moment to be spent eagerly awaiting his return. Seeing this the younger son Rohan makes a promise to reunite the family and bring back the happiness they once shared.