Europe, in the future: Since mortality has been overcome, the entire continent has merged into a single megacity of gigantic residential towers. Only the rich and powerful can afford a carefree life in the upper floors, while the majority of the population struggles to get by on the lower levels. When Officer No. 717 is assigned to track down the leader of a terrorist group, he becomes embroiled in a conspiracy that reaches into the highest echelons of society and threatens to disrupt the brutal order.