Back in March 2017, Harry Potter author J.K. Rowling revealed (after playfully teasing fans ) that the title of her next novel would be Lethal White. No, this is not the name of a deadly new Harry Potter adventure, but rather a continuation of the Cormoran Strike crime series she writes under the pseudonym Robert Galbraith . Lethal White — which will be released on Sept. 18, it was announced Tuesday — is the fourth book in the Galbraith/Strike series, following A Cuckoo’s Calling, The Silkworm, and Career of Evil .

Lethal White presents Strike with a new case when a troubled young man named Billy comes to his office to ask for help investigating a crime he thinks he witnessed as a child. Despite the weirdness of Billy’s story (“I seen a kid killed…. He strangled it, up by the horse”), Strike detects sincerity and decides to investigate alongside his assistant-turned-agency-partner Robin Ellacott. As Strike and Robin pursue the truth of Billy’s story through the backstreets of London, a secretive inner sanctum within Parliament, and a beautifully sinister country manor house, they’re pursued by new challenges. Strike’s newfound fame makes it hard for him to operate the way he once did, and Robin’s invaluable contributions to the business make her personal relationship with Strike rather tricky.