The end of us by Olivia Kiernan

It all started to go wrong the day the Wrights moved in next door. Myles and Lana Butler live on a gorgeous new development in Wimbledon, leaning on a mortgage that is just within reach. When one of Myles’ investments fails they are bound to lose everything. Gabriel and Holly Wright have just moved in next door. The Wrights are sophisticated, ambitious and apparently very wealthy. At an after-dinner drink with their new neighbours, Myles and Lana share their worries and a solution is suggested between the couples. Life Insurance fraud. For a cut of the pay out, the Wrights would help them. No one thought they were being serious. No one agreed they’d actually go through with it. And no one mentioned it would involve murder. Then, one night, Lana doesn’t come home.