Mumbai-based wealthy Sanjay Singhania is the Chair of Air Voice, lives now as a semi-crazed recluse in Odyssey Apartments in Hiranandani Complex. He was loved by Kalpana Shetty, a spunky and compassionate ad model, who rescued 25 young girls from the clutches of a gangster named Ghajini Dharmatma, but ended up getting killed by him. Sanjay has put together his past life piece by piece through tattoos, notes on his wall, Polaroid photographs, etc.. not knowing that soon he will be investigated by Inspector Arjun Yadav; betrayed by a 'friend' named Sunita; while Ghajini and his goons are out to erase every bit of evidence he has gathered in his apartment and thus ensure that he ends up remembering nothing