We Solve Murders by Richard Osman

Great condition. 

Steve Wheeler is enjoying retired life. He does the odd bit of investigation work but he prefers his familiar habits and routines: the pub quiz, his favourite bench, his cat waiting for him when he comes home. His days of adventure are over: adrenaline is daughter-in-law Amy's business now.

Amy Wheeler thinks adrenaline is good for the soul. As a private security officer, she doesn't stay still long enough for habits or routines. She's currently on a remote island keeping world-famous author Rosie D'Antonio alive.

Which was meant to be an easy job ...

Then a dead body, a bag of money and a killer with their sights on Amy have her sending an SOS to the only person she trusts. A breakneck race around the world begins, but can Amy and Steve stay one step ahead of a deadly enemy?

'The biggest phenomenon in fiction since Harry Potter'

Guardian