A Perfect Time by Lina Langley

Rio Alcázar is tired of small-time hit jobs.
Especially small-time hit jobs that send him to the ass-end of Florida when half the state’s underwater, the other half is covered in mosquitoes, and he’s on the trail of a small-time scientist whose kill fee won’t even buy a cheeseburger with 2291 inflation standards.

He’s desperate. Hard up for money. Doesn’t know what to do.
Until the biggest hit of all comes in.
A high-value contract. An under the table job. And…a priest.
In 1612.
What the hell.
Rio isn’t sure why the priest needs to die. But suddenly the scientist he’d meant to kill is his only ally as he hopscotches through cities and time, chasing Friar Lyons down a rabbit hole that takes Rio closer to home than he’d ever wanted to be. With his tech assets cut off by centuries and oceans, Rio’s on a countdown, at a loss, and not sure he can even pull this off. Especially when hunting Lyons through the past may change Rio in ways that could make or destroy his future…as he races both Lyons and himself to meet his mark in perfect time.