Time's Assassin - Mason Timeline, #0

In 2073, the once-mighty United States teeters on the brink of economic collapse, its industries in ruins, and Christianity a distant memory. But for those who make it through Warner University, the world's only time traveler training facility, wealth and freedom are still possible. Now the youngest student ever to travel in time, Alfredo Jaramillo is sent to 1688 London with Dr. Storm, his advisor, and Monica, his competent but annoying security liaison.
Once back from the trip, Alfredo's future will be set and he'll have his pick of jobs. But it all goes horribly wrong and Alfredo's grief is eclipsed only by his need for vengeance. When Alfredo deserts his mission on a quest for blood, Monica faces an impossible choice: protect the timeline at any cost or risk everything to save her mission partner. In a world where the past is fragile and the future isn't promised, only one thing is certain: time is running out, and the clock is ticking.