They All Fall Down by Rachel Howzell Hall
I am a huge Agatha Christie fan, so when I was They All Fall Down is an adaptation of And Then There Were None, I was of course interested. Seven people are lured to an island in Mexico and if you've read/seen And Then There Were None, you have a basic idea of what's going to happen. In this case, I don't think it's much of a spoiler to say they all end up dead.
The setting is great, an isolated private island in Mexico with a gorgeous house. The premise is obviously good, it worked for Christie, it works here. The people gathered each have their own secrets that have now caught up with them. The characters are mostly memorable if a bit caricature-ish. I didn't like any of them, but I wasn't supposed to either.
The story is told in the first person by Miriam, a dance mom who has some definition. She is not a nice person...