Tamanchey fires off when boy, Munna, a rustic kidnapper from Uttar Pradesh meets girl, Babu, a street smart drug peddler from Delhi. As criminals go, they meet in police custody while being escorted to jail.
Their romantic saga ensues when they get a dramatic chance to escape. During this escapade they are forced to stay together for a short period. By the time they've reached the end of their journey and potential freedom, Babu chooses to walk away, without warning. In her moment of doubt she chooses her familiar world of crime and ambition over her emotions for Munna.
The dejected lover, Munna, follows her to Delhi only to find that she's the mistress and right-hand of an uncouth, merciless and possessive gang leader, Rana.
The determined Munna steels himself and joins Rana's gang with the intention of eloping with Babu. This time Babu caves in to her feelings and thus begins their clandestine love affair right under the nose of the dangerous gang leader in the underbelly of Delhi's crime world.
In this dangerous world, they can only be together and evade Rana's scrutiny as long as they continue doing what is expected of them as criminals. They have to peddle drugs and engage in robberies. These acts of crime are their romantic dates, their treasured moments of being together. Rana is oblivious to their romance, happy counting his growing wealth from Munna-Babu's criminal adventures.
Their robbing sprees cause havoc in the city and the law is after them with a vengeance. Matters reach a point of no return when a robbery goes wrong and they end up killing a cop. They now have to retreat to a hide-out along with the gang lord Rana.
This brings an abrupt end to their romantic tryst. To make matters worse, Rana takes the decision to leave the country along with Babu. It is time for Munna - Babu to face their fears and confront Rana. Knowing Rana, this can only mean one thing - kill Rana.
However, not only does their plan to kill Rana fail, their secret affair gets exposed. They are now on the run not only from the law but also from Rana.
With the world of law and the world of crime after them, they know they have to make some hard choices. Their dreaded fears come true when they are cornered by Rana. However, yet again, they get a narrow chance to escape when a shoot-out happens between Rana's gang, the police and Munna - Babu.
This time they manage to at least get even with Rana. They kill him and are able to give a chase to the police. However the law is still after them and they both know that this cat-and-mouse chase with the law is unsustainable. It is not the life they want anymore. They would rather live as free, fearless lovers even if it meant serving time and waiting it out to be together.
But the law has other plans and is not looking to arrest them but to eliminate them. Is penance possible for Munna -Babu or will they too be exterminated in another statistical encounter?