S4, E1: After the body of Dr. Stephen Black is found on an Oxford tour bus, Lewis and Hathaway are lead to Crevecoeur Hall, a sprawling Oxford estate where Hathaway spent much of his childhood. Lewis begins to worry that a previous case involving the murder of ten year old girl has begun to affect Hathaway’s state of mind, whilst Hathaway himself seems more interested in the glamorous Scarlett Mortmaigne, the daughter of the owner of Crevecoeur. When another body is discovered on the estate, Hathaway’s refusal to believe that the family are involved threatens to tests his relationship with Lewis to breaking point.