Damadamm! is about Sameer who has finally got his long-awaited freedom when his stubby-girlfriend Shikha leaves for a family wedding. He feels like the happiest person in the world, and makes merry like there is no tomorrow by partying, drinking and flirting with other girls. He enjoys his freedom while he can, until Shikha shows back up.
The rest of the story converts into a Diwali-gift for the whole family.