High school freshman Jessica Walsh is a Virago—a woman warrior who must protect her hometown from danger. And in Nightshade, California, trouble is always lurking. At the town's Battle of the Bands, Jess's boyfriend, Dominic, and his band, Side Effects May Vary, are up against Hamlin, a band so popular, their fans follow them everywhere. Soon, the competing musicians are doing risky, illegal, and even fatal things—and claiming that they heard strange music that compelled them to do it. Can Jess and her friends track down the tuneful tyrant before it's too late?