The world's biggest religion has a problem. There is zero archaeological evidence for the original Eucharist - the sacred wine said to guarantee life after death for those who drink the blood of Jesus. The Holy Grail and and its miraculous contents have never been found. In the absence of any hard data, whatever happened at the Last Supper remains a mystery for today's 2.5 billion faithful. The Immortality Key attempts to crack the best-kept secret in history by examining the archaic roots of the ritual that is performed every Sunday for nearly one third of the planet. Two thousand years in the making, religion and science converge to paint a radical picture of Christianity's founding event. In the tradition of David Grann's Killers of the Flower Moon and Douglas Preston's The Lost City of the Monkey God, Muraresku takes the reader on his twelve-year global hunt for proof. He gains access to the hidden collections of the Louvre Museum to show the continuity from pagan to Christian wine. He spelunks into the catacombs under the streets of Rome to decipher the lost symbols of Christianity's oldest monuments. He breaches the secret archives of the Vatican to unearth manuscripts never before translated into English. And with leads from elite archaeological chemists, he unveils the first scientific data for the ritual use of psychedelic drugs in classical antiquity.