A beautiful but strange teenage girl is kept isolated by her mother and grandmother. Her long absent father arrives with a new fiancé in tow, and asks for a divorce. It's not long before all sorts of slightly perverted and typically violent seventies shenanigans kick off!
One of the oddest early seventies psycho-thrillers... as Marguerite, Locke is all bug eyes, long hair and mini-dresses as the disturbed teenager, wafting around, talking to a seemingly imagined friend and enduring alarming mood swings. Hasso and Ure (in her last film) are given rather thankless roles as her sinister guardians (and given the apparently Canadian setting - references to Charlottetown, Georgetown - there's no particular explanation for Marguerite having a Swedish grandmother and an Anglo-American mother... and why is the gardener British?). Robert Shaw was a fine actor (and he was married to Ure at the time), but here seems to sleepwalk throughout the movie, despite the slightly incestuous nature of his character, and Kellerman was a curious and strange choice for the 'straight' role of Anne, especially if you consider her other more wacky roles of this period (M*A*S*H, SLITHER, LAST OF THE RED HOT LOVERS and BREWSTER McCLOUD).
In keeping with a movie-making trend of the period, much is made of Locke's pubescent sexuality (see also BABY LOVE, TWINKY, Sally Tomsett's character in STRAW DOGS), and even with the apparent editing, the murder of at least one character has a grainy, improvised and rather nasty look to it.
Ultimately it doesn't really work, but it's still a fascinating and spooky failure with a striking cast and captivating central performance, all of which leaves it lingering long after the final credits fade.