'Unforgotten' Season 4, Episode 4 Recap: The Incident At The Ifield

Last week's episode of Unforgotten Season 4 was pretty heavy on the mystery details, leaving little room for the outside lives of either Cassie or Sunny. This week makes time to focus on how their lives are going in different directions: Sunny on the up-and-up as he leans into Sal, while Cassie's collapses into rage. The latter gets more screentime, with Cassie insulting her son, Adam, when he comes back with the truth her father's dementia isn't clouding his choice to wrap Jenny into his will. And she won't listen to John to let it go, upending a conversation where he hopes to get her to focus on the future and their relationship with the impending move.

But the worst part comes when Cassie forges ahead with the case over Sunny's protests. Her relationship with Khan is the one thing she's never screwed up. But between the racial dynamics of the case and her refusal to listen to his caution, it's slipping into dangerous territory.

There are huge developments this week, starting with everyone's favorite pathologist, Dr. Leanne Balcombe (Georgia Mackenzie). (Typically, her one-and-done appearance comes in the premiere to help identify the body.) Episode 4 finally brings her lab around to confirm Walsh's cause of death now that the head is here, though if it was a murder or a terrible accident where Walsh tripped and fell in an allotment and got stabbed by a garden implement is not clear.