My Initial idea of a teaser trailer

My initial idea is a thriller, aimed at youth audience of 15-24 as between those ages all the cast members will be. It starts off with black and white flashbacks of a brown haired girl (aged 12ish)and a brown haired boy both fighting at school, this is the result of the boy bullying the girl which is illustrated through black and white still image flash backs. The reason for him bullying her is later revealed in the film but it’s because she's been diagnosed with a split personality and is slightly different compared to other children. I would use a sound effect of children in a playground played on the top of this to create a spooky effect. After this it would go to a scene focused on a boy and a girl whilst there at a house party; the boy is a brown haired good looking guy and the girl is a busty blonde stereotypical female.
There a couple and this will be signified as the girl will be sat on the boys knee and all their friends will be around them but slightly blurred using depth of field too keep them in focus of the camera.
The following scenes will be about the party, showing what typical teenagers get up to and will include scenes of romance. However an argument is brewing between the couple as the girl, is a countertype of a blonde and wants to leave early as she has to revise for school the following morning whereas the boy wants to stay and play games with his mates. Throughout these scenes a brown haired girl will be in the background watching the pair, although nothing seems weird about this yet. Over the next couple of shots the couple are seen at school but don't appear to be talking to each other, there is a shot of the girl talking to her mates about him and the brown haired girl is comforting the blonde haired girl.
The narrative follows on by the boy receiving weird phone calls to start with, this then progress's to death threats being put in his locker at school and through his letterbox. However his ex-girlfriend is getting the blame, the audience at this point are unaware that its actually the brown haired girl who is getting revenge for her troubled childhood.Towrads the end of the film all 3 characters are at a party, when the boy forgets his mobile phone and goes home to get it...however he is being followed by the brown haired girl, unknowingly to him. As he goes into his house where everybody is out in...He enters his room and hears footsteps, the boy runs but the girl follows him around his house at this point the main character still thinks it’s his ex-girlfriend. He manages to turn on a light and finds out who his stalker really is however just as he does she comes running into him with a hot iron and knocks him out. The girlfriend has come looking for the boy as he's been a while and was wanting to sort things out with him, when she comes into the house she sees her ex-boyfriend and her friend still with the iron in her hand, the girl starts to scream and the girl with the iron runs after her but the film ends on that and the audience never find out if she catches her or not. As i would like to make a second film with the conclusion in.