Sehar's (Ayesha Takia) world turns topsy-turvy after a Sunday went missing from her life - a day which she cannot remember what happened. ACP Rajveer (Ajay Devgan) takes on the case to sort out the complicated and jumbled up threads of Sehar's life. In the process of solving Sehar's case, it comes to light that on that Sunday, different people had interacted with her and amongst them, one could be a murderer. The lot included Ballu (Arshad Warsi), the taxi driver and his friend, Kumar (Irrfan Khan), a struggling NSD actor, Ritu (Anjana Sukhani), Sehar's close friend, a scary and suspicious character who resides in Sehar's society, and the group whom she had come across while partying at the discotheque. While trying to solve the puzzle, Rajveer stumbles upon a murder case upon which the evidence seem to implicate Sehar. But she cannot remember anything. Her fiance ACP Rajvir Randhava is convinced that Sehar is innocent, but he is also equally sure that she is linked to everything.