Tanvi and Sanju are living a rather comfortable life in a quaint little town, but Tanvi is not really happy with her husband's habit of not keeping his promises. He is a typical marketing guy, very shrewd, sly and good at making excuses at the last moment. She hates how he never really pays attention to her and always busy with his work. Tanvi for long have wanted to get couple tattoos done and Sanju had promised last year that they will definitely get inked on their next anniversary. But the truth is that he really dislikes tattoos. The anniversary is approaching day after tomorrow, so she reminds him of his promise; but he brushes off the subject once again. Tanvi tries to convince him and tells him that getting inked is trendy, and even her best friend Ruchi's husband got one recently. To which he retorts that Ruchi's husband is having an extramarital affair too, so does that mean he is supposed to follow the suit on that as well. Frustrated by his evasive attitude, she throws a magazine at him and notices a pamphlet falling out from the magazine. It is about tattoo service on call. Determined to get back at her husband by surprising him with a tattoo, Tanvi decides to call at the given number.Next morning Tanvi wakes up screaming from a horrible nightmare, which seems too real. Still shaking with fear, she goes to the kitchen to drink water and tries to make sense of the dream where she kills Sanju at his own insistence. Feeling paranoid by constant voice in her head urging her to kill Sanju, and a strange engraving of some sort of a sigil on her wrist, she almost jumps when suddenly Sanju touches her shoulder from behind. He asks if everything is alright, to which she replies that everything is fine. Later on, while leaving for office Sanju promises Tanvi that she should be ready for a big surprise, but Tanvi is all engrossed in what might have happened yesterday. All she remembers is just bits and pieces of her conversation with tattoo maker, but what happened after that and how did she end up in bed and most importantly, does Sanju know about this. She decides to call Sanju to discuss and comes out on the balcony, and notices the same tattoo maker standing at the corner of her building, expressionlessly staring at her. She runs downstairs to catch hold of him, but when she reaches the spot, he is nowhere to be seen. Bewildered whether she actually saw him or it was just hallucination, she looks for clues in the house, leading to an address written on some visiting card that seems odd for it is of a secluded and run-down building where no one lives anymore. Tanvi decides to visit that place to find answers, oblivious to the fact that it is indeed a trap and she would have no point of return once she is inside that house.Tanvi enters the deserted house and sees tattoo maker sitting in a room with his back to the door. She notices a box on the table and eventually starts remembering the events of last two days while going through the items in that box. There are many pics with strange markings on wrists, including hers. Scared but determined to know the truth, Tanvi confronts him but he seems unaffected by her presence and keeps smoking silently. Tanvi tries to hit him when suddenly tattoo maker put out the cigarette by rubbing it on his wrist, where a sigil is marked. Tanvi groans with pain and faints. Unaware of all this, later at night Sanju quietly enters the house and finds Tanvi working in the kitchen. He had bought ticket of a music concert 'Timeout' to surprise her. As he approaches her, shouting surprise, she turns around with a flashing knife in hand, slicing Sanju's neck with the sharp blade. Blood trickles down his neck and in a deserted place the tattoo maker just about finishes the death sigil by marking number six. As Sanju dies, the Sigil starts disappearing from tattoo maker's hand, leaving the tattoo maker almost stunned. He gets up and walks towards a box hidden with black sheet. As he opens it, a corpse opens her eye. Tanvi back at her house is mumbling and blankly staring at the wall.Revolving around three central characters and told in a non-linear narrative, six is a story of necromancer and a special sigil that transfers the bad luck to the person who gets inked.