On July 2, a giant alien mothership enters orbit around Earth and deploys several dozen saucer-shaped 'destroyer' spacecraft that quickly lay waste to major cities around the planet. On July 3, the United States conducts a coordinated counterattack that fails. On July 4, a plan is devised to gain access to the interior of the alien mothership in space, in order to plant a nuclear missile.
Prima ballerina, Dominika Egorova faces a bleak and uncertain future after she suffers an injury that ends her career. She soon turns to Sparrow School, a secret intelligence service that trains exceptional young people to use their minds and bodies as weapons. Dominika emerges as the most dangerous Sparrow after completing the sadistic training process. As she comes to terms with her new abilities, she meets a CIA agent who tries to convince her that he is the only person she can trust.