The third book in the Dark is Rising Sequence, unites the Drew children (from Over Sea, Under Stone) with the immortal young Will Stanton from The Dark Is Rising, and the result is not always effective. Will's character comes from a dark world of magical power, while the Drew children are from a mystery/adventure story. Will's maturity and acceptance of his duties as an Old One can be interpreted as cockiness in comparison to the Drew children's lack of supernatural power. However, the kids have grown up since the first tale, especially in the case of Jane.

Jane's role is crucial in the acquisition of the manuscript. It is she who communicates with and understands the Greenwitch's secret and her anguish. Celtic folklore is woven through the story, and readers learn some Greek mythology in the realm of Tethys. Some new discoveries are made: We meet Captain Toms, the absent sea captain and the owner of Rufus from the first book. The children sense something different about Will and notice how he addresses Great-Uncle Merry as Merriman and not "sir." They even observe him speaking in an ancient language.

From the Book:
Nervously Jane followed. As she came close to the Greenwitch she felt again the unimaginable force it seemed to represent, but again the great loneliness too. Melancholy seemed to hover about it like a mist. She put out her hand to grasp a hawthorn bough, and paused. "Oh dear," she said impulsively, "I wish you could be happy."