Assassin's Choice - E.L. Reeves

Alyssa is the best assassin in her guild. She earns the best contracts and always, always completes her mission. When a wide contract sends every assassin in the area on a hunt for a fugitive, she is determined to get there first.

But when the contract goes awry, and they fall through a tear in the fabric of reality, she finds herself marooned with her target on a strange new world. With no way to get home and unfamiliar with the local customs, the two take a job pulling off a heist at the royal palace.

Surrounded by an unknown crew and growing closer to the woman she was supposed to kill, Alyssa must work out a plan to steal a relic from under the royals' noses while keeping ahead of unknown pursuers and figuring out what to do with the strange woman she failed to kill.