During an away mission, Riker falls unconscious and awakens to discover that sixteen years have passed, and he is now captain of the Enterprise. Having no memory whatsoever of the time that has passed, he begins to suspect that the future he finds himself in may not be real.
CommanderRiker's birthday celebration is interrupted as he, Geordi La Forge, and Worf are sent down to a huge underground cavern on Alpha Onias II, an uninhabited Class M planet, to investigate unusual readings. After their arrival, the cavern suddenly fills with toxic gases, and the three officers fall unconscious.
Riker awakens in sick bay to find that sixteen years have passed. He is now Captain of the Enterprise with Data as his first officer, and Picard has been promoted to admiral, with Deanna Troi serving as his aide. Riker cannot remember any event after the Alpha Onias III mission, which Doctor Crusher explains is a side effect of a viral infection he contracted on the planet, and his memories of the intervening events may or may not return in time.
Riker learns that he was married, is now widowed, and has a son (Chris Demetral) named Jean-Luc (named after Picard). He is further startled when Tomalak — a Romulan commander who was formerly an archenemy of the Enterprise, now an ambassador — beams onto the ship to negotiate a peace treaty with the Federation. Despite Picard's reassurances, Riker is hesitant to reveal sensitive Starfleet information in negotiating the treaty.
As Riker struggles to adjust to his new life, numerous inconsistencies arise. The Enterprise computer is uncharacteristically slow, numerous systems experience minor technical glitches, and Geordi is unable to correct the problems. Finally, Riker discovers that his late wife "Min" is Minuet, a fictional holodeck character he fell in love with (in the first-season episode "11001001"). Riker realizes that the entire "future" he has been experiencing is a charade and confronts Picard and Tomalak on the Enterprise bridge, with more inconsistencies arising as he does so, proving his suspicions. Suddenly, the false future fades away, revealing a Romulan holodeck. Commander Tomalak is revealed to be behind the simulation, the object of which was to trick Riker into giving away the location of a key Federation outpost. The Romulans, Tomalak explains, were fooled by the intensity of Riker's memories of Minuet and had incorporated her into their fantasy on the assumption that she was real.
Riker is put in a holding area, where he meets the boy whose image the Romulans had used to create his "son". The boy identifies himself as "Ethan". Together, they manage to escape and briefly elude their Romulan guards. However, as the two are hiding from their pursuers, Ethan inadvertently refers to Tomalak as "Ambassador", instead of "Commander". Riker realizes that he is still in a simulation; confronting Ethan over it, he demands that the game end immediately and that he be allowed to leave.
Everything disappears once more, leaving only Riker and Ethan back in the cavern on Alpha Onias III. Ethan confesses that he had created the simulations, using sophisticated scanners to read his mind and create the "reality" he experienced. Ethan's planet had been attacked and his people killed; his mother had hidden him in the cavern for his own safety, with all the simulation equipment, before she died; and Ethan, all alone, had been yearning for companionship. Riker realizes Ethan's intentions were not hostile, and after Ethan reveals his true form as a grey-skinned insectoid alien named Barash, Riker offers him refuge on the Enterprise. Riker is then able to contact the ship, and learns that Worf and La Forge had beamed up without incident, but the Enterprise was unable to locate him. Barash accepts Riker's offer, and the two beam onto the ship.