Sehar(Ayesha Takia) goes clubbing with her best friend Ritu (Anjana Sukhani) and gets drugged with date rape drug Rohypnol and loses her memory of what happens next. Monday morning brings her tons of surprises in the form of a taxi driver Ballu (Arshad Warsi) who wants his taxi fare, some thugs who want to kill her and a wannabe actor (Irfan Khan) who thinks shes a ghost. A girl has been found murdered with seemingly no connections whatsoever to Sehar. The twist in the story is that another man has been murdered the same night Sehar loses her memory of. As her to-be-beau ACP Rajveer (Ajay Devgan) tries to reconstruct the events of the missing Sunday, the mystery deepens and finally bursts open in an unexpected climax.