The fourth volume of The Dark is Rising series begins with Will traveling to Wales to stay with a cousin of his mother's, so he can recuperate from hepatitis. The young man is troubled because there is something important he forgot. On the way to the cousin's home, he sees clouds around a mountaintop, which helps him remember one part of a prophecy spoken at the end of the third book, Greenwitch. The woman's son, Rhys, says the clouds are the breath of the Grey King, a legendary figure whose home is there.
Another clue to the gap in Will's memory is Cadfan's Way. As he explores the church of St. Cadfan and searches for this lost road, he has a curious encounter with a dog. All his memories come back. He meets a boy, Bran, who knows his true identity as an Old One and who says he has awaited him. The Dark awaits him too. "All around, throughout the countryside, he [Will] could feel the malevolence of the Dark growing, pushing at him."
But this time, the Light is not there merely to defend all from the devouring Dark. This time, it is actively on the attack against it.
This series is much more interesting when it focuses on Will, as this one does. I love through the series how descriptive the author is. It is no wonder these are classic fantasies.