Masquerade

 Masquerade is the season finale of Book One.

Plot
The five girls race against time to deploy traps set by yet another mole at the annual masquerade ball.

Synopsis
The episode starts out with Mia practising in the ballet studio alone, while thinking about ways to thwart Tara's chances on getting the regent scholarship for the Royal Ballet. She is practising on the barre but soon starts some sort of routine.

Meanwhile, Mia's boyfriend, Nick Cavanaugh, is traveling to the Academy to be Mia's date for the ball at Moose and Arcadia's request. A waitress brings him hot coffee (so soon? he asks) and he looks out the window and smiles.

The calm beginning is then interrupted by Brooke and Moose rocking out to loud heavy metal music in Brooke and Mia's dorm room while eating SmoothTheRoom smoothies. Arcadia comes in, looking for Mia, but the two girls don't hear her. Arcadia then finds Mia at the ballet studio, training for three hours. The two leave to go to the courtyard only to get into a snowfight with Ben and Anubis. Finally in peace in Arcadia and Moose's dorm room, they discuss their costumes for the night, with Mia confessing something : She doesn't know whether or not to tell her boyfriend about the Academy.

The scene then changes to where the four Primes stand around a wisp, showing some sort of bad premonition. Thalia and Jacqueline look at each other, and then back at the wisp.