The Reverend Samuel Parris, Minister of Salem, follows three strangers in the forest beyond the village - a forest which is traditionally believed to be the source of much evil. He hears movement through the trees, steps forward and makes a terrible discovery. It is one which will change life in Salem forever. The TARDIS arrives in Salem Village, Massachusetts, 1692. The Doctor wishes to effect repairs to his ship in peace and privacy, and so his companions - Ian, Barbara and Susan - decide to 'live history' for a week or so. But the friendships they make are abruptly broken when the Doctor ushers them away, wary of being overtaken by the tragic events he knows will occur. Upon learning the terrible truth of the Salem witch trials, Susan is desperate to return - at any price. Her actions lead the TARDIS crew into terrible jeopardy, and her latent telepathy threatens to help the tragedy escalate way out of control...