Badi dooooor se aaye hai is a story of 5 extra-terrestrial people, from a different galaxy. They have come to earth in search of their lost son. These 5 aliens consist of a father, mother and their 3 children. Few years back they had lost their youngest son while travelling through our galaxy. Since then they have been searching for him from planet to planet .This hunt of theirs had got them to our planet earth.

Detective Dev Anand Burman battles inner demons caused by the death of his wife Mahek. He has become a recluse but still works on criminal cases with Inspector Amod Narvekar. The Inspector believes that Dev murdered his own wife. Dev befriends his landlady Zohra Aapa who treats him like a son. Later, he meets fire-brand Meera who forces him to reassess his life.

Shilpa, a student, loves Kartik, a doctor who is married. Everything starts to crumble when Kartik's wife becomes suspicious about his affair.