Willow's trying to earn a little pocket change by taking the usual teenage part-time job -- baby-sitting the neighbor's kid. But her child-care chores turn into a scene from a horror movie when the baby gives her the evil eye and attacks. Barely escaping the tiny terror, Willow can't forget the missing human child -- or the monstrous thing left in its place. The childish changeling keeps coming back to haunt and taunt her.
Buffy and her posse soon discover a possible connection between Willow's infant interloper and some strange artifacts Giles found at a local archaeological dig. The evil plaguing Willow was once trapped underground. Now that it has been unearthed by new construction on the property, it's ready to cause some major mischief...and worse.