A Message From Charity - S1.E15

In 1985, a fever-stricken Peter Wood finds himself in telepathic contact with Charity Paine, a sick girl his age living in Puritan New England. The two rejoice in sharing their thoughts, and Peter gives Charity the chance to see things that she'd never experienced in her limit time and place. However, their new-found contact turns to horror when Peter's knowledge of the future endangers Charity's life. She inadvertently speaks of the future, causing the villagers to believe she is a witch. With help from Peter, she convinces the witch-hunter to drop the case by hinting she can reveal information about him that Peter has found in the future. Eventually their contact breaks, but Peter receives one last message telling him to look on a rock...where the words "CP+PW" are inscribed.