Sun-hee, a veteran cashier and mother of two, works at a large retail supermarket alongside Hye-mi, a single mother. Both are friendly with Soon-rye, a cleaning lady nearing retirement age, and all of them are temporary workers. Sun-hee is a model employee who works diligently in the belief that once she gets promotion (rank) as a permanent employment, she'll be able to provide more for her children. However, their corporate employer abruptly notifies them that all the temporary workers will be layoff. Faced with these wrongful dismissals, Sun-hee, Hye-mi, Soon-rye, and fellow female employees such as naive ajumma Ok-soon and twenty-something Mi-jin, resolve to go on strike action. They stage a series of increasingly impassioned protests against the company's exploitative practices, which gains more strength when junior manager Dong-joon, the only male representative of the store's trade union, joins in. The shy and passive Sun-hee, who finds herself thrust to the demonstrations' front lines, discovers within herself untapped resources of determination and resilience, which has an unexpected effect on her relationship with her estranged high school-age son, Tae-young. But as the women realize the power they can wield by taking a mutual stand, the company plays the workers against each other and Hye-mi, the leader of the strike, caves to the company's pressure and gives up.