Trapped is the fifth novel in Kevin Hearne's Iron Druid Chronicles. A Harry Dresden-esque story of Atticus, the last remaining druid.
Atticus largely spends his time hanging out, loving the earth and being all druid-y. This is how he has stayed alive when all the other druids were killed off! The series, however, shows how events unfold to lead Atticus in bringing the magic back and training an apprentice, a hot one. In book five it appears Granuaile, said apprentice, is ready to be sworn in or, conveniently "bound," when everything goes awry.
I really enjoy these books. They are clever, fast paced and a good escape. Hounded is the first in the series.
Trapped (The Iron Druid Chronicles, book five) by Kevin Hearne