Magpie is a thirteen-year-old orphan chosen by one of the magical Companion horses of Valdemar and taken to the capital city, Haven, to be trained as a Herald. Like all Heralds, Magpie learns that he has a hidden Gift-the Gift of telepathy.

But life at the court is not without obstacles. When Mags is "recognized" by foreign secret operatives whose purpose is unknown, Mags himself comes under suspicion. Who are Magpie's parents-who is he, really? Can Mags solve the riddle of his parentage and his connection with the mysterious spies-and prove his loyalty-before the king and court banish him as a traitor?