Earth’s ecological collapse is avoided when most of the world population agrees to permanently upload into Replika, a simulated reality maintained by the AI. But the stability of this world is threatened when a group of neuroscientists hack their own brains to interact with Replika in unforeseen and dangerous ways. Sky devotes her life to rebuilding the real world left dysfunctional from the massive exodus into Replika. But when she learns her brother, who disappeared under mysterious circumstances, is in danger, she must choose which world needs her most. All she wants is to find the brother she loves, but she will unwittingly get entangled in a complex attempt to redefine the reality of humanity’s future.