Tumsa Nahin Dekha is a love story of Daksh Mittal (Emraan Hashmi) and Jia (Dia Mirza). Daksh Mittal is a charmingly witty and perpetually drunk millionaire. He comes across a working class girl Jia, shoplifting at a mall and it's love at first sight for Daksh. He subsequently discovers that Jia is actually a striptease dancer.
But unfortunately for Daksh and Jia, the timing of this romantic encounter is odd. Daksh is scheduled to marry a properly pedigreed society girl Anhaita Madhwani (Pooja Bharti) whom he detests. But if Daksh doesn't marry Anhaita the heiress, he will not inherit the million-dollar trust.
So Daksh turns to his loyal butler, John Uncle (Anupam Kher) for help. John who wishes to see Daksh prevail, stage-manages a situation in which the true lovers will come together and get the loot.