Guardian (Book Two of the Spirits' War Trilogy)

You mess with one of the Three, you mess with them all. The Battle of the Ritual may be over, but the war against the Covenant has only just begun. Skye and her companions head to Canada in search of more recruits and for Sejka's long-lost brother. Meanwhile, Mac T re, Ace and Greg remain in the U.K. to seek an old ally: the great dragon Nwyfre. But when the L og Airgid's worst enemy, Patercius, resurfaces to join forces with the Covenant, the Three must rely on fleeting memories from past lives to take down their enemies new and old.