As an autistic scholarship student at the prestigious Webber Academy in New York City, Waverly is used to masking to fit in--in more ways than one. While her classmates are the children of the one percent, Waverly is getting by on tutoring gigs and the generosity of the school's charming and enigmatic dean. So when her tutoring student and resident "it girl" asks Waverly to attend the school's annual fundraising Masquerade disguised as her, Waverly jumps at the chance--especially once she finds out that Ash, the dean's daughter and her secret ex-girlfriend, will be there.

The Masquerade is everything Waverly dreamed of, complete with extravagant gowns, wealthy parents writing checks, and flowing champagne. Most importantly, there's Ash. All Waverly wants to do is shed her mask and be with her, but the evening takes a sinister turn when Waverly stumbles into a secret meeting between the dean and the school's top donors--and witnesses a brutal murder. This gala is harboring far more malevolent plots than just opening parents' pocketbooks. Before she can escape or contact the authorities, a mysterious global blackout puts the entire party on lockdown. Waverly's fairy tale has turned into a nightmare, and she, Ash, and her friends must navigate through a dizzying maze of freight elevators, secret passageways, and back rooms if they're going to survive the night.

And even if they manage to escape the Masquerade, with technology wiped out all over the planet, what kind of world will they find waiting for them beyond the doors?