Two years after the first Shadow invasion Bobby, Sam (Samantha), Jeffrey, plus their friends Delia, and Amy, are drawn into a dangerous mystery. At the end of the first Shadow invasion, the rift to the Shadow world is closed, trapping a Shadow witch, Overseer Shadow Strong, and thirty seven of her Shadow witch warriors in this world. They hide from the humans using the Soul Eater Spell that lets them take over the bodies and lives of humans. Shadow Strong begins planning a new Shadow invasion but instead takes malicious actions that lead to an invasion of an even more dangerous demon race called the Formorians.

Once again, the heroic group of young Americans, now eighteen and about to graduate from high school, are forced to test their courage and skills further to defeat a new, more powerful enemy and a horrific war that changes the hero's lives forever. "In battle against evil, such as demons and other monsters," Master Maeda said. "Always go for the kill. Otherwise the wrong person, a friend, a comrade or a loved one, may end up dead." Shadow Invasion: Shadow Witch combines the elements of science fiction, fantasy, and the supernatural.