The TARDIS lands on the Northumbian coast, where new companion Steven discovers a viking helmet and the Doctor deduces they must have arrived in the 11th century. Steven remains sceptical, especially when he and Vicki encounter what appears to be a Saxon wearing a wristwatch. Investigating a nearby monastery, the Doctor discovers further anachronisms. Who is the mysterious monk observing the time travellers’ every move, and why is he so interested in the Battle of Hastings?