Jesus Was a Time Traveler

Time travel. Every sober scientist claims it's utterly impossible. Of course, Phineas Templeton is no "sober" scientist, in any sense of the word. An arrogant English chap with a taste for fine scotch, Dr. Templeton also happens to be one of the finest minds the world of physics has ever known.
By the year 2032, with funding from his shadowy Benefactor, he put the finishing touches on his time machine. His mission? Travel to ancient Judea and meet none other than Jesus Christ Himself.
There's only one problem: upon his arrival, Dr. Templeton finds that "Jesus" is actually a time traveler from the future, a stoned grad student from Colorado named "Trent Albertson." Trent explains that history is fixed and immutable: "What happened, happened," no matter what meddlesome time travelers do during their stays in the past. The reality we experience is little more than the sum of the actions of countless time travelers that have already come, gone, and influenced the timeline, provided a very fickle universe allows them to.
Upon attempting to return, Phineas is presented with an unusual new mission: a "scavenger hunt" through time, where if he is able to decode his Benefactor's cryptic clues and complete the tasks at hand, then maybe, just maybe, he'll be able to return home.
But first, he'll have to meet his hero, Sir Isaac Newton, rescue a couple of American soldiers, survive an all-out attack by ancient Mayans, and even hunt dinosaurs millions of years in the past. Through it all, Dr. Templeton hovers on the fringes of his sanity, uncovers a vast conspiracy spanning thousands of years, and deals with existential questions that will shake you to your very core.