The Kind Worth Killing by Peter Swanson

Strangers meet in an airport bar and end up planning a murder. Is it just folly, or will they follow through?

Ted's a rich dude with a cheating wife and a mansion under construction. Lily is a librarian with no connection to Ted, and a plan that might help him. But wow is this twisty, and even right up to the last line there's a surprise.

I picked up this pop suspense novel because a friend said she couldn't put it down. And I have to say - I didn't see it coming, and that's not what I thought would happen. (Which is the highest praise I give - I hate it when books are super predictable!)