When her beloved Moonsilver, the unicorn, is nearly killed by a hunters arrow, Heart sneaks back into her village to get help froth the healer, Ruth Oakes. But even greater danger awaits Heart and Moosilver in Ash Grove. Rumors of Monsilver's secret have reached the ears of the cruel Lord Dunraven. Once again Heart must flee, with Ruth's mysterious gift -- a silver thread -- to protect her and Moonsilver.