Something chilling lurks underground, and two step-siblings must unite to uncover the truth in this "engrossing mystery" ( Booklist).

Katie knows that something eerie is happening in the old, deserted town where she, her stepbrother, and her newly widowed mother are spending the summer taking care of Uncle Frank. Sometimes, when Katie puts her ear to the ground in Uncle Frank's backyard, she hears a groaning noise that sounds almost human. But when a crippled ghost-girl appears to her out of the gloom in an abandoned mine, Katie is at once terrified and puzzled. Could the girl's chilling appearance have something to do with a tragic mining accident thirty years before? In a fiery climax, Katie and her rebellious stepbrother learn the truth about the past and discover things about each other that strengthen their fragile relationship.