Every Last Liar by Kate Francis

All of them are guilty.
All of them must play the game.
But only one can survive.

On the first anniversary of a tragic fire at their high school, seven teenagers jump at the chance to attend a luxury desert retreat. But when they’re left at a rundown abandoned motel and a sinister text message accuses them of complicity in the fire, they realize someone is playing a deadly game of revenge.
The rules? Every hour, one of them must sacrifice themselves, leaving the motel to be killed, until only one survivor remains. Otherwise… they all die.
As the countdown begins, the stranded must answer the questions: when everyone’s guilty, who deserves to live? Who deserves to die?

With time running out, can they work together to uncover who’s running the game before the bodies pile up? Or will it be survival of the fittest?