Delia Ephron, like her late sister Nora, is an acclaimed screenwriter. Nora wrote When Harry Met Sally and Sleepless in Seattle. Delia wrote You’ve Got Mail and Michael (John Travolta as an angel).

More recently, Delia has written a number of novels and the latest is Siracusa (Point Blank £12.99). But don’t think Meg Ryan rom-coms. Siracusa is different. Very different.

It tells the story of two dysfunctional, American, fortysomething couples. Michael is an acclaimed playwright/author. He is married to Lizzie, a journalist who is no longer getting assignments. They are childless. Michael is having an affair but Lizzie doesn’t know it. Lizzie used to go out with Finn, who is now married to Taylor. They have a 10-year-old daughter, Snow (she was born in a blizzard). Everyone thinks there’s something a bit odd about Snow, a bit mysterious. Or is she just shy? Is her mother, Taylor, the real problem? The two couples go on holiday together to Italy, ending up in Siracusa in Sicily. That’s when everything kicks off.

The book is an odd mix. It’s part psychological thriller, part chick-lit. With all those lies and betrayals going on, you know someone is going to come a cropper but, until late on, you don’t know who. You also don’t know if it will be just a couple breaking up, or something much, much worse.

Two things redeem it. First, there’s a great twist at the end. Second, the writing. It’s a fast, fun read, perfect for a beach holiday. Sassy, smart, knowing. Pure Ephron.

Richard Aronowitz could hardly be more different. Ephron is in her 70s and grew up in Beverly Hills. Aronowitz is 30 years younger and grew up in rural Gloucestershire. She has movies in her DNA. He heads the Restitution Department at Sotheby’s.

An American Decade (Accent Press £7.99)  tells the story of a young German tenor, Christoph, who comes to New York in 1930. His wife, Ida, has just died and he is “a lost soul”. She was Jewish, he is not. He crosses the Atlantic in search of a new life and meets Anne, a young American waitress. They fall in love and marry. There’s just one problem. Hidden away in a box in their apartment there is a bundle of letters to him from Ida’s sister, Miriam…

Aronowitz’s novel is a slow burn but, as the mood darkens in Germany, it packs a terrific and moving ending. He has done his research into 1930s America and there’s something plausibly selfish about Christoph. His politics are thoroughly decent but the way he treats women is not.

At first glance, these two novels could hardly be more different. Rich Americans with wandering eyes on holiday, poor Germans with wandering eyes in 1930s America. And yet both are about men betraying women, men with secrets and how people with good intentions can hide something truly rotten.

David Herman is the JC’s chief fiction reviewer