Nicholas Konstantine gets in the way of a cheesy robbery at San Francisco's Asian Art Museum and finds that he is the new owner of a statue older than civilization itself, depicting the god Mithra. The crude idol confers elemental powers, but they're doing Nick more harm than good. He can't just ignore the situation, however, because a splinter group of religious fanatics is determined to end the world on time, andunfortunately for the rest of usit's up to Nick to stop them.
Nick, chronically unemployed, isn't much of a hero, but Mithra isn't much of a god: He's more of a building superintendent. Until the two pieces of Mithra's Keyone being the idolare joined, he has no physical power over things of the earth. It's up to Nick to keep the idol out of the hands of his shadowy enemies, the "Sons of Khorasan." Nick is a bit distracted, having just fallen in love with Rita, a sensible physical therapist of unlikely beauty. But while trying to hide his increasingly odd behavior from her, and playing keep-away with the "Sons" as well as the SFPD, he also must find the other half of the key, already held by the Sons' unknown leader, and put the halves together.