[3] Puneet Bajpai (Ajay Devgn), a movie scriptwriter, lives with his Bengali interior-designer wife Munmun (Konkona Sensharma) and their six-year-old son Ayush in a high-rise apartment in Goregaon in Mumbai.

The couple's happy life is upended when Lambodar Chacha (Paresh Rawal), a distant uncle of Puneet's, turns up unannounced one morning and slaps the guard, causing a commotion.

Lambodar interferes in every aspect of their lives, from forcing the maid to quit her job after she is tired of being ordered around by him (much to Munmun's dismay), to incessantly trying to catch Puneet's attention, to bringing in strangers as newly formed friends he met on the way or calling him when he is not around.

Others, however, are impressed by his display of devotion at the local temple, or his apparent ability to cure backaches by kicking the sufferer in their rear.

One day Puneet brings Lambodar to his film set, built on a grand scale and directed by the well-known Ranjeet Taneja.

The couple books a hotel room one night along with Ayush, but Puneet is arrested when a police raid discovers him apparently 'molesting' Munmun.

On the occasion of Ganesh Chaturthi, during the immersion celebrations at Juhu beach, Lambodar goes missing in a stampede, and Puneet spends the night at a hospital hoping he was not killed.

At this point a second son of Putani's arrives — the actual Pappu — and asks Lambodar to stay at his home, apologising profusely for the confusion as his flat number was the same as Puneet's but in a different tower in the same housing society.

The collections picked up through good word of mouth and sustained well at the box office for eight weeks despite competition from other films and IPL cricket tournament held during the same time.

Author and cartoonist Abid Surti has sued makers of Atithi Tum Kab Jaoge claiming that the story is directly lifted from his Gujarati novel Bauter Varas No Babo published in 1976, which was later translated in Hindi as Bahatar Saal Ka Baccha.