Laal Singh Chaddha narrates the story of Laal Singh who is suffering from cognitive difficulties. We are taken through his journey as a child living with these problems, challenges he faces during his childhood, and how he met his first childhood girlfriend Rupa. After Rupa's mother passes on and her father is arrested, she moves to Laal's home to stay with her Aunt who happens to be Laal's house-help. The bond between the two gets strong, we are taken through their education journey, career and their marriage life until the death of Rupa.