Clothes of Sand (Dark Shadows)

The Sandman is coming... he's singing the children to sleep everywhere.... When Maggie Evans is taken to the Windcliff Institute, she begins her recovery from the ordeal she suffered at the hands of Barnabas Collins. As she undergoes hypnosis, disturbing memories of her childhood begin to surface. Who was the imaginary friend who once watched over her, and what threat does he pose for Maggie's future?