Sixteen-year-old Jenny Agutter plays Wynne, a young teen infatuated with her much-older adoptive brother. When a serial killer murders women in the woods near her new housing estate, she begins to suspect him.

In I START COUNTING (1970), Wynne moves with her family from her childhood home in the country into a cramped flat in a new-town tower block. She still sneaks back to the old house, now slated for demolition, to relive memories of George, her grown adoptive brother, played by Bryan Marshall. As bodies turn up in the woods nearby, Wynne starts noticing things about George that frighten her, and she cannot decide whether to trust him or turn him in.

Agutter made this just before The Railway Children and Walkabout made her a star. Her performance holds the film's central tension, a girl discovering longing and dread at the same time, in the same person.

David Greene directs from a script by Richard Harris (not the actor), adapted from Audrey Erskine Lindop's novel.