The Devil's Elixir - Raymond Khoury

What if there was an herb, previously lost to history in the jungles of Central America, capable of inducing an experience so momentous it might shake the very foundations of Western civilisation? What if powerful forces on both sides of the law got wind of that herb, and launched a violent, uncompromising pursuit to be the first to exploit it? And what if FBI agent Sean Reilly and his girlfriend, Tess Chaykin, were, unknowingly, the only two people who could keep the lid on this existential Pandora's box, one that's capable of destabilizing the world? Sean and Tess find themselves in a race-against the clock, against drug kingpins, and even against the government, as they follow two divergent trails, one several hundred years old, the other as current as a heartbeat, which together may lead humanity to the brink of annihilation.