Plot ideas

The first plot we came up with together was ;

A mum and a son are walking through a forest. The small boy runs to fetch a ball which he loses in the leaves. As he turns around to look at his mum he sees her lying on the floor with a man standing over her wearing a white mask, at this point the killer does not know the kid is watching. As the is standing over the body the kids gasps, this alerts the killer that the boy is there, the killer turns to look at the kid with the mask on. He slowly takes it off and puts it over the mothers face and walks off. The film then goes forward in time and zooms out of the mask where the kid who is now older is staring at the mask, while staring at the mask on his friends face he hears the same whistling tune.