It all begins with a meteor shower. Soon after, reports spread of so-called Immortals. Each time they die, their bodies reset to an earlier point in time, with every wound, scar, and even the smallest scratch gone. Humanity is thrown into chaos, unable to explain the strange phenomenon. Two hundred years later, scientists still haven't been able to uncover the mystery of immortality. The Immortals now live in hiding: hunted, captured, and exploited as test subjects. They are forced to live, unable to die. Then, a rumor begins to spread of a man known only as the Undertaker— the one who can kill the Immortals. (Source: WEBTOON)