In 1850, on adjoining farms near Concord, Massachusetts, live Sally and Amanda, cousins so inseparable their brothers call them Salamander, suggesting they slip and slide into mischief. Strange activities at a neighboring farm intrigue the girls. At night, weird shadows lurk behind curtained windows. The reclusive farm owners have no visitors and reject neighborliness. When Sally and Amanda tell their brothers about shadowy figures and whispers on the wind, the boys respond with stories of witchcraft and sorcery. The girls vow to avoid the farm but curiosity drives them back to the house. One night they stumble on their neighbors’ secret-and willingly become part of it. The farm is a station on the Underground Railroad where two run-away slaves-children, like themselves-are hidden. Caught up in a plan to help them escape, the girls confront evil and endanger themselves and their families.