All Beth has to do is drive her son to his Under-14s away match, watch him play, and bring him home.

Just because she knows her ex-best friend lives near the football ground, that doesn’t mean she has to drive past her house and try to catch a glimpse of her. Why would Beth do that, and risk dredging up painful memories? She hasn’t seen Flora for twelve years. She doesn’t want to see her today, or ever again.

But she can’t resist. She parks outside the open gates of Newnham House, watches from across the road as Flora and her children Thomas and Emily step out of the car. Except… There’s something terribly wrong. Flora looks the same, only older. As Beth would have expected. It’s the children. Twelve years ago, Thomas and Emily were five and three years old. Today, they look precisely as they did then.

They are still five and three. They are Thomas and Emily without a doubt – Beth hears Flora call them by their names – but they haven’t changed at all.

They are no taller, no older… Why haven’t they grown?

“WHEN YOU’RE YOUNG, YOU DON’T SERIOUSLY WONDER WHETHER YOUR FRIENDS MIGHT BE TERRIBLE PEOPLE. YOU’RE NAIVE AND OPTIMISTIC; YOU ASSUME ANYONE OCCUPYING THE STRUCTURAL POSITION OF BEST FRIEND MUST BE A GOOD PERSON DEEP DOWN.”

This was bonkers.

It’s been six years since I’ve last picked up a book by Sophie Hannah (!) and having adored A Game For All The Family, Haven’t They Grown was high on my list. I honestly forgot what an insane and enjoyable crime thriller writer she is!

Listen, was the whole thing entirely implausible? Absolutely. Did I care? Not at all.

Haven’t They Grown is a wild ride. After Beth takes the wrong turn dropping her son off at footy, she glimpses her old friend, Flora, and her children. 12 years have passed since their friendship came to an abrupt end but something is wrong; the children haven’t aged. They should be in their late teens, but they appear to still be exactly the same as age and when Beth last saw them.

Gripping from start to finish, Haven’t They Grown is packed to the brim with twists and a constantly evolving plot. Just when you think you know what’s happening, Hannah throws a spanner in the works and the mystery of Flora’s ever youthful children becomes so impossible to solve that you’re left scratching your head in utter confusion. The ending, as far-fetched as it is, is so twisted, I truly couldn’t have predicted it. At one point, I was convinced it was aliens. Sadly, the actual explanation was far less supernatural and somehow far more twisted than if they had been cloned by aliens.

Beth as a protagonist was an interesting one. I went back and forth between admiring her determination or being annoyed by her and her family. None of the characters in Haven’t They Grown are particularly likeable, but I didn’t love Zannah. The attempt at Gen-Z humour was a tad forced at times and many side plots were included that just didn’t go anywhere.

Still, the way Hannah writes the overarching mystery is so engaging. With each passing page, I became more and more addicted. I needed to know what exactly was going on! My brain was literally fried by the end. I can’t believe it’s taken me this long to read another Sophie Hannah novel! Recommendations of more of her work are welcome.

RATING

★★★★