The Ink Black Heart is the name of a popular fictional cartoon. Its creator, Edie, contacts the agency online about abuse she's receiving from a mysterious figure known only as Anomie. Robin rejects Edie's request but a few days later, news breaks of the woman's death after her body is found in Highgate Cemetery, where the cartoon is set.
Strike and Robin immediately take it upon themselves to unearth Anomie's true identity and discover whether the abuse is linked to Edie's death. "But with a complex web of online aliases, business interests and family conflicts to navigate, Strike and Robin find themselves embroiled in a case that stretches their powers of deduction to the limits - and which threatens them in new and horrifying ways," reads the official synopsis.
Alongside that, Strike and Robin's will-they-won't-they dance is set to rumble on, particularly now that Robin's divorce from Matthew has been settled – he's expecting a baby with Sarah and the pair are also set to marry.
At the end of Troubled Blood, Strike bought Robin a bottle of perfume for her birthday, before the pair headed off for a solo dinner together. It was the perfect setting for a passionate kiss and for a moment, it looked like they were going to go there. But instead, Strike took the opportunity to tell Robin that she was his "best friend".
Strike and Robin standing facing one another, Robin holding a balloon
Tom Burke as Cormoran Strike and Holliday Grainger as Robin Ellacott in Strike. Troubled Blood Limited MMXXII, Laurence Cendrowicz
While it wasn't the romantic turning point viewers were hoping for, and possibly expecting, it was very sweet, nonetheless. But will they finally make a go of it in season 6?