New York City, 1956: Nineteen-year-old Marion is over the moon to have been selected to be one of the Rockettes, Radio City Music Hall's glamorous precision dancing troupe. It's an honour to perform in the world's most spectacular theatre, an art deco masterpiece. But with four shows a day as well as grueling rehearsals, not to mention exacting standards of perfection to live up to, Marion quickly realises that the life of a Rockette has both extraordinary highs, and devastating lows. Then one night a bomb explodes in the theater. It's only the latest in a string of explosions around the city orchestrated by a person the press has nicknamed the Big Apple Bomber, who has been terrorizing the citizens of New York for sixteen years by planting bombs in popular, crowded spaces. With the public in an uproar over the lack of any real leads after a decades-long manhunt, the police, at Marion's urging, turn in desperation to a radical new technique: psychological profiling. As Marion finds herself pulled deeper into the investigation, she realises that as much as she's been training herself to blend in-performing in perfect unison with all the other identical Rockettes-if she hopes to catch the bomber, she'll need to stand out and take a terrifying risk. In doing so, she may be forced to sacrifice everything she's worked for, as well as the people she loves the most.