Submerging (Book 3 of The Starlight Chronicles

With his birthday coming, Hamilton Dinger, better known as "Wingdinger," Apollo City's part-time superhero, has more than enough on his plate. But with Aletheia, a new supernatural ally, her sister, the Star of Time, Elysian and Hamilton set off for the Celestial Kingdom to deepen his commitment through learning, new landscapes, and cosmic surfing. Can he learn enough to hold off the evil forces of the Seven Deadly Sinisters?