Doctor Blakk is gone and his ghouls are cured, but the Shane Gang's journey is just beginning. Everything the slingers think they know begins to crumble when the impossible happens again and again, and Alana Caelum is realizing the world is much bigger and more complicated than she ever could have imagined. Her past is catching up with her just as fast as her future is crumbling, and new threats are rising from within the 99 Caverns and beyond. [Takes place during Ghoul From Beyond and Return of the Elementals, and after the fanfiction 'Take Back the Light.']

Things have changed in the five years that have passed since Will Shane's disappearance. Without their protector, the 99 Caverns are becoming more and more dangerous. Blakk Industries is slowly taking over the realm's slugs and industry. Doctor Blakk seems bent on ruling the realm. Without her guardian, Alana's been living with only the company of her slugs. Determined to keep a positive view on her life, she's focused on training to become the slugslinger that Will would have helped her be, despite wondering about herself and her strange new abilities that are appearing. But when Will's son takes the Drop to Slugterra, Alana has to put her own life on hold to help save her home.