In December 1984, Ken Webster, a high-school teacher, was living with his friend Nic and girlfriend Debbie in the small village of Dodleston. One evening, the three were walking home from the local pub when they saw a pulsing green light emanating from their cottage windows. When they got inside, they saw something that terrified them. Though their computer wasn't connected to any network, and everyone in the house was gone all night, a strange message was written on the screen. A message addressed to them, by name. Over the next few months, more messages appeared. Eventually, Ken and his friends begin corresponding with the person on the other side. At first, Ken thinks this is a hoax or a prank. But over time, he comes to believe that not only are the messages real, they're being written by someone living in the very same house -- in the year 1541