Polly O'Keefe, back for another adventure, is called into the prehistory of the druids. Polly's first autumn at her grandparents' Connecticut country home is glorious and peaceful. But when she takes daily strolls as breaks from her studies, even openminded Polly is nonplussed by three people she spots--especially when she learns that they date from 3,000 years ago: exotic Anaral, majestic Karalys, and warrior Ta, who intrigues Polly as no other young man ever has. Soon she crosses the "time gate" into the pagan past, where she eventually takes part in a territorial dispute. Polly's friend Zachary, desperate for a cure for his heart disease, accompanies her and--once again in a L'Engle story--love's redemptive power sets crucial events in motion after Zach surrenders Polly to a blood sacrifice to secure his own healing. L'Engle is still an able practitioner of time travel, yet even she seems to be wearying of the many explanations and logical twists required for suspension of disbelief--and/or belief--and the "tesseract." Here, the conceptual feats aren't quite so original, invigorating, or accessible. But her storytelling skill (a blend of practiced writing and theological roving) will carry even nonbelievers along while--in her attempt to reconcile pagan with Christian belief--the notion that Christ existed long before the historical Jesus is superbly debated.