Nine year-old Nicki Johnson attends a funfair with her parents. Her father takes her on a merry-go-round ride, where Nicki becomes frightened. Attempting to reach over to comfort her, her father instead falls from the ride and is crushed to death in its machinery. The tragedy leaves Nicki traumatized, particularly as in its aftermath she overhears comments suggesting that she was to blame for what happened, which leave her with a permanent sense of guilt.
Seven years on and Nicki (Hinde) is a troubled and confused teenager living with her mother, plagued by flashback nightmares and with an obsession with horses and riding stemming from the merry-go-round horror. Since being widowed, her mother Anne (Renée Asherson) has withdrawn emotionally from her daughter and has sought consolation with a succession of younger lovers. Her latest boyfriend Harry (Mower), who Nicki detests, is a sleazy con-artist who makes his living out of latching on to wealthy older women and fleecing them financially before moving on. Nicki is left largely to her own devices and often plays truant from school, spending the time with her boyfriend Peter (Waterman).
Returning home one day from a riding lesson, Nicki finds herself alone in the house with Harry. He attempts to seduce her, and when she proves resistant, taunts her with the fact that her trust fund is now in his control. A struggle ensues, during which Nicki stabs him several times leaving him seriously injured. For her trouble, she is sent to a remand home for young women with emotional and behavioral problems. —Wikipedia