Story and how the opening sets it up

The overall plot of the Thriller is very simple, and involved only two characters. A young girl, Ruby, and an older man named Len.
Typically, Len is an older man posing as a young boy in order to "groom" young girls, Ruby being the latest victim.
The shots are set up in mainly 2 locations. Ruby's bedroom and Len's garage/office.
Len entices Ruby enough to make her meet him in a park. It is here that he lures her to his home. As she enters the home, Len begins his perversion. Ruby enters his "office" filled with various tools, pictures of young girls and women and his laptop. As Ruby begins to feel Len's perverted wrath, she tries to exit...

We have shot the openings sequence as an almost flashback. The opening ends as the pair finally meet, though the camera views them separately and not together. The rest of the film would be what happens after the pair have met. Len's perversion and Ruby's struggle to escape.