PBS is running these old episodes as a lead-in to the new season, something they didn't bother to do with Endeavour, so we sat there trying to remember what happened at the end of the season.
As a result of a staff shortage, DI Lewis returns to the force temporarily. Hathaway is now a DI and is working with DS Lizzie Maddox to investigate arson on a hunting ground. The grounds are owned by Alistair Stokes, a surgeon, and Tom Marsten. The grounds were purchased from Gillian Fernsby, who continues to live on the grounds.
She's a suspect when Alistair Stokes is found shot, but by no means is she the only one. One of his underlings, Simon Eastman, reported him as being drunk during a delicate brain operation where the patient wound up a vegetable. The boy's parents are definite suspects. And both men had been receiving threats from animal rights activists.
Marsten is arrested when it's learned that his gun fired the fatal bullet and that he increased Stokes' insurance. Lewis is unsure of his guilt, especially when there is another shooting with Marsten's gun -- which is sitting in the evidence room at the station.
Good episode with little camaraderie between Lewis and the newly- promoted Hathaway. They need to somehow get that chemistry back, and Holloway needs to find his sense of humor again. However, given that he's new to the job, it's probably natural that he's very serious.
Lewis is either married to or living with Laura, who isn't happy about him being away from home so much. We'll have to see what happens there.
Looking forward to the new episodes.