Dream Demon (1988)

Diana is a high class young woman with a troubled past, who is on the verge of marrying the caddish Oliver. Spending the night in her old and spooky family mansion, Diana stares into a mirror and begins experiencing terrifying dreams. She sees her past, present and future, while at the same time entering a dark dimension of her own. One day Diana is visited by her friend Jenny, an American tourist and also a victim of a turbulent past. Without knowing how or why, Diana suddenly pulls Jenny into her nightmarish world.