Sum of Existence is an extraordinary film that breaks with one of the most cliché'd traditions of psychological thrillers -- the idea that hypnosis is a panacea that can be used to solve problems. In fact, the story centers around the way that the use of hypnosis takes a girl who has already been brutally wounded and unbalances her in ways that almost get her -- and others -- killed.
Liz Murphy is a normal, vivacious teen, who was brutally assaulted by a stranger and left to die. Months after the attack, she lives in a strange sea of denial and confusion. Attempting to go about her normal life, she doesn't understand why so many people treat her differently, even her best friend and her parents, nor why she's periodically haunted by strange, frightening flashes of... something...
What Liz doesn't know is that, in the aftermath of her attack, she broke down so completely that, as a last resort, her parents turned to a psychiatrist who used hypnosis to block her memories. In the short term, it helped her to recover. But it's left her behaving in ways that her friends and family find disturbingly out of character, and THEY are still dealing with the fallout of what happened to her, even if she no longer is. Worst of all, her assailant is furious that she's forgotten him, and is determined to make her remember.
Although a lot of the conventions of the traditional thriller are in place, including the cat-and-mouse game that soon develops between Liz and her stalker, what truly distinguishes this film is the way it delves into the minds of its characters. It explores Liz's fragile state, and the way simply burying a trauma such as hers only worsens its impact. It explores the mind of her psychiatrist, a woman who becomes far too attached to her patients and can't always discern (because she's lost her objectivity) what is truly best for them. And it explores the mind of the twisted psychopath who has become obsessed with Liz's destruction.
Brooke Anderson is a luminous actress, definitely one to watch. She makes Liz's plight very real, and yet manages, even when Liz is at her worst, to imbue the character with a quiet strength that comes to the fore. Liz is nobody's victim, and her mind is nobody's playground, and watching her take back her life and her sanity is a very triumphant experience.