Silver on the Tree by Susan Cooper

This book is the final episode in the Dark is Rising series, and I gave it a rating of four out of five. All of the main characters from the previous books join forces in the decisive battle between the Light and Dark. Will must venture into an alternate world with Bran, who turns out to be the son of King Arthur, in order to acquire a silver sword hidden in a tree. The Light and Dark are unable to use their powers in this world, and Merryman is not available to help Will. Simon, Jane, and Barney also encounter the Dark forces in the modern world, but everyone comes together for the climax. The side in possession of the sword will hold a huge advantage in the final battle.

This plot is harder to follow, much like book two, because much of the setting and events are hard to imagine. The battles aren't always fought with swords and shields, as the forces uses magic to do their fighting. This series is definitely for advanced readers who enjoy fantasy worlds.