Physically fit specimens (an Air Force pilot, a football player, a cop) are all being targeted for a grisly death: their hearts are being cut from their chests while they're still alive, with a dull blade, on higher and higher flights of steps. Kolchak investigates and spots a strange feathered creature near the scene of one of the murders. He finds out that an ancient Aztec cult is trying to resurrect their ancient god, Nanautzin, the Lord of the Smoking Mirror. Since his destruction at the hands of the Conquistadores 520 years ago (the Aztec millennia), his worshippers must sacrifice the hearts of five worthy victims every 52 years. Upon the completion of the final cycle, Nanautzin will be restored to life. However, the final death must be a ""perfect sacrifice"": a willing victim who is given his every wish for a year before his final death. Pepe, a box boy, is the ""perfect sacrifice"" and Carl must track him to the highest staircase in Chicago and convince him to back out of the sacrifice.