The game begins as humanity welcomes the first alien delegation to visit the planet, and prepares to answer positively to an invitation to join the interplanetary "Symbiotry of Peaceful Beings". During the induction ceremony, the government-operated Temporal Security Agency (TSA), which was established to enforce prohibitions on time travel and safeguard the timeline, detects three temporal disturbances that have altered history; the Agency mobilizes Agent 5 to correct the disruptions, which have altered the timeline so that the Symbiotry never extended its invitation.