The Soul Thief Book 2 of The Chronicle of Franklin

Ghosts get stuck sometimes. Franklin sees it as his duty to help them along, get them to pass from this earth to the Beyond. But some ghosts start returning. Haunting Franklin. Destroying his crops. Franklin learns he must use an ancient, powerful blade to force the ghosts back Beyond. However, someone else wants that blade, for purposes that involve life and death, not just for the ghosts, but for all the living as well.