When Charlotte Gray, Luna Harrison, and Michael Taylor are chosen for a perilous quest, they find themselves thrust into the heart of an ancient and terrifying mystery. Tasked with retrieving a powerful artifact hidden deep within the Vault of Endless Night, the three demigods-each with their own strengths, fears, and secrets-must face a deadly adversary: the Shadow King, a being of unimaginable darkness with the power to consume the world. As they battle relentless monsters, unravel cryptic prophecies, and struggle to keep their sanity in the face of evil, they discover something even more dangerous than the Vault itself: each other. With Luna falling prey to the shadow king's influence, Charlotte's wit and cunning, Michael's strategy, and Luna's healing powers are put to the ultimate test. Forced to work together, they learn that their bond is the only weapon powerful enough to defeat the shadows-but their journey is far from over. In this high-stakes adventure, old friendships will be tested, new ones forged, and the line between light and dark will blur. The Vault may have been conquered, but the true battle is just beginning.

The story follows these four friends-Kai, Emma, Z, and Lily-who discover a hidden secret about Oakstone Manor, an abandoned mansion on the edge of their town. Strange occurrences have surrounded the manor for years, and despite its eerie reputation, no one has dared to investigate. That is, until the group of friends stumbles upon a mysterious journal that hints at an old treasure hidden inside the manor. As they delve deeper into the mystery, they find themselves faced with puzzles, strange phenomena, and the looming question: What happened at Oakstone Manor years ago, and why does it seem like something-or someone-doesn't want them to uncover the truth?