Intangible (Piercing the Veil, Book 1)
by C.A. Gray
The first of the "Piercing the Veil" YA Fantasy trilogy. Peter, Lily, and their friends must come to grips with a world of Arthurian legends and shadow creatures they never knew existed before. One of them is the Child of the Prophecy, destined to destroy an ancient evil who calls himself the Shadow Lord. When Peter's father is abducted, they find themselves in a race against time to save him.