In this episode, the Enterprise responds to a distress call from a Romulan science ship. Lieutenant Commander Geordi La Forge and Ensign Ro Laren are lost in a transporter accident when returning to the Enterprise with a faulty generator from the Romulan ship.

As the Federation starship Enterprise responds to a distress call from a Romulan ship which has suffered an on-board explosion, Ensign Ro and Lieutenant Commander La Forge are seemingly lost in a beam-in from the Romulan ship to the Enterprise. Ro and La Forge find themselves on the Enterprise, unable to interact with the ship or the crew, but able to interact with each other. While La Forge believes they are still alive, Ro sees Dr. Crusher make out their death certificates and believes they are dead; she tries to make peace with her former crewmates as they prepare a funeral service. Commander Data traces the cause of the transportation accident to the Romulan ship. Ro and La Forge go along with Data and Lt. Worf as they fly a shuttlecraft to the Romulan ship. Aboard, La Forge discovers a phase inverter device, and theorizes that he and Ro are out of phase, and thus undetectable. He also overhears the Romulan crew discussing a plan to transmit a signal to the Enterprise that will cause the warp core to explode the next time the ship enters warp. The two return with Data and Worf to the Enterprise to try to warn the crew, unaware that a Romulan, also out-of-phase, is following them.

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