On the outskirts of Sunnydale, recent heavy rains have uncovered the remains of a five hundred-year-old Spanish expedition. There were many artifacts found alongst the ruins of the Spanish expedition, but one of the artifacts, a beautiful smokey mirror with a special ornately carved Obsidian frame, goes missing along with the history teacher who found it. And while on patrol Buffy narrowly escapes an attack from a black jaguar, Giles and the rest of the Scoobies go into research mode.

An ancient volume identfies the missing mirror is a magical object designed by the Aztec god of darkness. Any mortal that looks in the mirror will see his or her fate, which can be manipulated by the evil god, who is trying to regain his power. Taking their destinies into their own hands, Buffy and the rest of her friends rush into a ferocious fight between light and darkness in the shadows of a massive Aztec Temple.