Greenwitch

Greenwitch by Susan Cooper is the third book in The Dark is Rising sequence. The first book Over Sea, Under Stone stars three Engish siblings Simon, Jane, and Barney and their great-uncle Dr. Merriman Lyon, affectionately called "Gramerry", as they recover a Midieval chalice while beset by the forces of Darkness. The second book, The Dark is Rising, has Merriman orienting the newest of the Old Ones, eleven-year-old Will Stanton, and directing him in gathering the six Signs of the Light. In this third novel, all the children are together as they vacation in a coastal town (setting of Book One) and attempt to recover the parchment document containing the key to translating inscriptions found on the chalice.

Altogether a delightful, though short, book. I'm already a couple of chapters into the sequel, The Grey King.