Although he’s never met her, Strike hears from his half-sister Prudence Donleavy for the first time in Troubled Blood when she and Al want him to attend a party for their father, Jonny Rokeby.¹ Prudence appears to be slightly more understanding than Al is about Strike’s reservations and explains via text that she is also a result of their father’s “briefer liaisons” and that she too has had to deal with her own “share of hurt and anger over the years.” ²

Strike has no objection to meeting her but wants to wait until his life is less complicated.³

In The Ink Black Heart, during their evening at the Ritz, Strike tells Robin that Prudence is a Jungian therapist and that her mother is Lindsay Fanthrope, a mixed-race actress who has appeared in “everything,” including Eastenders and The Bill (Ch 1). 

Strike and Prudence arrange to meet, but Prudence’s daughter Sylvie has a climbing accident and the meeting is postponed. However, as the book ends, we hear that Prudence is visiting Strike that very evening (Ch 107).

^{1: Troubled Blood, Chapter 31
2,3: Troubled Blood, Chapter 34}