The Chosen

Cade Carter is convicted of a crime he didn't commit and is staring down a year in reform school when he's suddenly yanked out of his life and into a strange new world built from remnants of history: prehistoric creatures, ancient relics, and displaced people from different eras all thrown together.

Cade barely has time to get his bearings before he and his fellow captives are forced to become Contenders in a brutal, high-stakes game controlled by mysterious overlords whose goals no one can figure out. The only way out is to win, and Cade has to use every bit of instinct and cunning he has to survive it.

The first book in Taran Matharu's Contender series.