Day of Reckoning — Kai Strand

Twelve-year-old, Terra, not only learns she's a Nature's Spirit destined to serve the peaceful underground city of Concord, but she also finds that a prophecy names her as the only one who can thwart the leader of the death tribe. The Trepidus are the death janitors of the Underworld. They're responsible for the termination and cleanup of Concord's beings. When their leader, Blanco, learns Terra is the one who can derail his day of reckoning, he does everything he can to get rid of her. Including dispatch a Bringer to complete the ultimate of death janitor duties. Terra hopes to complete her training and discover her Spirit talents so, Frank, a Spirit of Security, is assigned to protect her. They undertake a secret investigation of how to defeat Blanco. But with the future of Concord and Terra's very own life at stake, will they find the answer in time?