At the request of Tigra, Earth's Mightiest Heroes travel to San Francisco to diagnose the mysterious ailment that has put Jessica Drew (aka Spider-Woman) into a coma. When the ghost of Spider-Woman appears at the hospital, the Avengers realize that supernatural forces are at work! So the call goes out for super-powered help, namely Doctor Strange and Dr. Henry Pym! But even the Master of the Mystic Arts and the world's leading biochemist don't know what or who is afflicting Jessica Drew! Could it be an evil sorceress from the sixth century? Time is running out...somebody needs to figure out something...and soon!