The opening scene would consist of a close up shot of a missing poster being nailed to a lampost. The close will also help us to establish an enigma of a keyring which will be the same as the missing girl.
Next would be the main character, in this sense the missing girl, and an over the shoulder shot of her walking towards the poster, with it then having an extreme zoom towards the poster,
In our next scene we are aiming to use over the shoulder shots with a shot reverse shot between the missing girl and a photographer in a flashback from the previous shot, where the picture being taken is the same picture as seen on the missing poster in reality. This would give the sense of seeing her face but not seeing the photographer's so creates that sense of mystery of 'Who is that man?'
We will next have another close up shot of after the flashback and the girl will be ripping the poster off of the lampost.
This shot would potentially be a longshot of the missing girl walking away from that lampost and walking down a tiled street. This would be even more effective especially if the weather would be misty and damp which would create a decent scene full of generic conventions and also mystery. We may also add a slight Tilt shot which will help to establish the sense of confusion and nightmare.
Once the main character of the scene walks down the street, she walks past a bin and we will have a shot of that character next to the bin, then going to a close up shot of her taking the ripped poster and keys out of her pocket. Bare in mind this key would be identical to the one the unknown character at the beginning. Another close up of her putting the poster and also keys into the open bin. Another character follows not far behind and picks the keys out of the bin using yet another close up shot, still not knowing who this character is however she turns around and notices the person taking out the keys which creates the enigmatic effect to the thriller. At this point she is acting fairly paranoid.
Cuts to the bus/train station and the girl is buying a bus ticket, close up on the handover of the ticket. She then walks past a photobooth where seletaped to it there is another extreme close up of an envolope with her name on and the same keys that she threw away.
Close up of her turning around slowly, and noticing a man sitting on a bench reading a newspaper. But notices something in his left hand where an extreme close up shows us the keyring again from both characters. A second extreme close up of the top of the newspaper where this enigmatic character moves the paper down slowly and we see his eyes. Shot reverse shot to the girl who knows who it is.
This is when the film would end leaving it on the cliffhanger of 'Who is this man?' and 'How does she know who it is?'
It also gives a sense of how the certain scenes will look from within the contents of the thriller film production.