Sophie Hannah

Hodder & Stoughton, £16.99, pp336

The premise of Sophie Hannah’s new thriller is entirely, darkly irresistible. It opens as Beth swings past the home of Flora Braid, a friend she last saw 12 years ago. Beth watches from her car as Flora unloads her kids; they haven’t aged a day. “This is the Emily Braid I knew 12 years ago, when she was three years old. And Thomas… I can’t see all of his face, but I can see enough to know that he’s still five years old, as he was when I last saw him in 2007.”

Back at home, Beth, her husband and her teenage children attempt to unpick how this could be. Perhaps Beth was hallucinating, they speculate. Or it was a mistake. Or, says Zannah, Beth’s daughter, the first two kids died, and the second lot were named in their honour. But: “I’ve had no other delusions or hallucinations. This isn’t part of a pattern. That makes me a reliable witness. I trust myself,” says Beth, who sets out to uncover exactly what’s been going on. From 2006’s Little Face, in which a mother insists her newborn baby is a stranger, Hannah has always excelled at the knotty, impossible twist and Haven’t They Grown is as complex and as sinister as ever.

Gerald Seymour

Hodder & Stoughton, £18.99, pp448

In the latest thriller from Gerald Seymour, Gary Baldwin is an “island recluse” on Orkney, a former special forces soldier who is suffering from post-traumatic stress disorder after witnessing unspeakable horrors in Syria. “If he were free of [stress] for a long time, years, not months, then there was a chance he could put the experience behind him.” When it seems as if the Russian officer responsible for the massacre, a man Gaz saw “become an animal in a feeding frenzy, a fox in a chicken coop”, has been tracked down in Murmansk, Gaz is asked to help identify him. The horror at the heart of this novel, “a story that would freeze blood” to which Gaz is witness, is revealed in small glimpses, almost impossible to look at head on, as the always classy Seymour expertly stacks up the elements of his story to create another intricate, absorbing thriller.

Catherine Steadman

Simon & Schuster, £12.99, pp384

Actor and author Catherine Steadman’s second novel opens on a Norfolk beach as a man wakes up, unable to remember who he is or where he is from, with just one word written on his hand. When he is unable to recall anything in hospital, neuropsychiatrist Dr Emma Lewis is called in to help. If he isn’t faking – he might be a fugue patient, his memory loss caused by trauma – this a case that could make her career. But there are government concerns around who the man might be and, worse for Emma, he was found on Holkham beach, not far from where she grew up. Emma, it turns out, has a shadowy past of her own and her work with this new patient is about to bring everything into the light. Moving between perspectives, Steadman slowly pulls back the curtains from the danger Emma is edging towards. The solution is overly convoluted, but it’s an enjoyable, nail-biting ride to get there.

Doug Johnstone

Orenda, £8.99, pp300

When Jim Skelf dies unexpectedly, his wife, Dorothy, daughter, Jenny, and granddaughter, Hannah, are left at the reins of his funeral home and PI operation. “The kitchen doubled as the ops room, from which both businesses had been run for the last decade, since Jim surprised everyone by announcing he intended to expand out of the death industry into private investigations.” As Dorothy discovers a series of secret payments made by Jim to another woman, Jenny looks into an adultery case and Hannah sets out to find her uni friend, Mel, whose disappearance the police won’t take seriously. A Dark Matter is the first in a new series from the criminally underrated Johnstone, whose Breakers, shortlisted for the McIlvanney prize, is a devastatingly bleak, touching look at the life of a teenage Edinburgh burglar. His warm portrait of the tough, indomitable Skelf women is gripping and blackly humorous – bring on the next one.

• To order Haven’t They Grown, Beyond Recall, Mr Nobody or A Dark Matter go to guardianbookshop.com. Free UK p&p over £15