The Bynars take over the Enterprise during a starbase refit.
The Enterprise docks at Starbase 74 for computer upgrades carried out by the Bynars, a species that lives in pairs and thinks in binary. While they work, Riker and Picard spend time in an improved holodeck program featuring Minuet, a jazz-club woman who seems remarkably real.
The Bynars then fake an antimatter containment failure, and the crew evacuates, leaving Picard and Riker aboard on the holodeck. The Bynars take the ship to their homeworld, whose central computer had been knocked out by a nearby supernova, and plan to use the Enterprise computer to store their planet's data.
Picard and Riker regain control, restore the Bynar computer and return to collect the crew. Minuet proves to have been part of the Bynars' plan to keep the two officers occupied.