S1E24 · We'll Always Have Paris

The Enterprise, along with other ships in the sector, experience a localized time-distortion and soon after receive a distress-call from Dr. Paul Manheim in a nearby system. Captain Picard (Patrick Stewart) recalls that Manheim was ejected from the Federation Science Institute for conducting unauthorized experiments; he feels awkward about meeting Manheim because he once had a relationship with Manheim's wife, Jenice, before abandoning her in Paris to become a starship captain.

They find the distress signal coming from a facility on a planetoid surrounded by a force-field. Manheim and Jenice are the only survivors of the research team, and Manheim needs immediate medical attention. The two are brought aboard and while Dr. Crusher (Gates McFadden) tends to Dr. Manheim, who is having convulsions, Jenice has an awkward reunion with Picard. She also alerts the crew to numerous security protocols that her husband has installed at the facility. As the crew prepares to send an away-team to investigate the laboratory, they experience more time distortions, described by Data (Brent Spiner) as "Manheim effects". In one instance Picard, Riker and Data enter a turbolift only to see their past selves conversing outside of the lift. The crew find that they cannot complete a transporter beam to the facility due to the security measures in place there.

Dr. Manheim recovers long enough to explain that he was doing experiments involving time, gravity and funnels to other universes and suspects his last experiment is running out of control. Manheim explains that he is trapped between two dimensions and Data determines that the experiment must be shut down during a time fluctuation or else it will simply grow larger. Manheim provides the crew with the correct coordinates to beam down to avoid the security fields. Picard admits to Jenice that he worried about losing her again after he left her in Paris and vows to correct Dr. Manheim's experiment.

As he is affected less by the distortions, Data is sent down alone and disables the remaining security measures before entering Manheim's laboratory. He finds a column of energy emanating from a dimensional matrix, the source of the time distortions. Data, though briefly affected by the time distortions, is able to add anti-matter to the matrix, causing the matrix to stabilize and halt the time distortions. Dr. Manheim recovers and he and Jenice thank Picard and the crew for their help. Picard and Jenice use the holodeck to recreate one more encounter at a Paris café, before she returns with her husband to the planet.