Moondial (1988)

Teenager Minty expects to spend a quiet holiday near historical Belton House with her mother's godmother, "Aunt" Mary. However, soon after leaving Minty, her mother is involved in an accident and lies comatose in the hospital. Distraught, Minty begins wandering the Belton grounds. When she touches the sun-dial/moon-dial in the garden, she is transported through time. First to the late 19th century where she meets Tom, a sickly and abused servant. Second to the 18th century where she meets Sarah, a mysterious cloaked child who is in danger. Can Minty find away to help these ghosts of the past?