The Puzzle Box Trilogy Omnibus. The Puzzle Box Trilogy

Bedridden for six months with Valley Fever, high schooler Libby creeps out of bed to see the beekeepers arrive on her father's farm. One of the beekeepers is a lich named Mal whose bees collect magic as well as honey. While his honey can cure her illness, Mal is embroiled in his own problems. He's trying to regain his humanity and avoid the Necromancer, who is determined that Mal will follow in his footsteps.
But as Mal and Libby delve into what is required to restore Mal's soul to his body, they run afoul of the Marchers, a group of magic users who protect civilization from evil creatures. The Marchers see Mal only as a monster to be slain, even as they hold the keys to helping him regain his soul. However, attempting this unleashes the Hunger, a vicious monster intent on devouring the living. As Mal and Libby's mutual affection grows, so does the danger enveloping them.
Will they succeed in restoring Mal's humanity, or will they bring about the zombie apocalypse?