An action crime thriller, Kate follows the titular character, a skilled assassin at the height of her game. But when she makes a careless mistake and compromises an assignment targeting a member of the Yakuza while in Tokyo, she discovers she’s been poisoned with a deadly serum that slowly kills her from the inside out, giving her less than 24 hours to exact revenge on her killers. As her body swiftly deteriorates, Kate forms an unlikely bond with the teenage daughter of one of her past victims.