When the Enterprise's sensors detect an incoming craft traversing the Neutral Zone for Federation space, the Enterprise moves to intercept. The ship's Romulan occupant requests asylum as he is being pursued by a Romulan Warbird. Both ships cross the Neutral Zone but the Warbird engages its cloaking device and heads back for Romulan space when the Enterprise begins protecting the other ship.
The sole occupant of the Romulan vessel is beamed aboard, identifying himself as Sub-Lieutenant Setal, an insignificant logistics clerk who acquired information about a top secret Romulan installation being crafted on the planet Nelvana III, capable of sustaining a fleet of Warbirds. Skeptical, Picard assigns Geordi La Forge to dissect the Romulan vessel, though it auto-destructs before he can do this.
Picard gets word from Starfleet Command that the Romulan government demands Setal's return. Geordi analyzes the vessels' earlier pursuit and reports that the Warbird had purposely slowed down to avoid capturing its target, suggesting an elaborate Romulan hoax. Commander Data launches a probe for any possible signs of a Romulan incursion, but no hard evidence can be gathered without physically crossing the Neutral Zone, thereby violating the Federation/Romulan treaty. On Ten-Forward, Setal Setal explains to Data that his defection has come with a very terrible price. In compassion, Data invites Setal to the Holodeck where he has programmed a simulation of the Romulan Valley of Chula, to which Setal stands in amazement. Moments later however, he dismisses the simulation entirely. He asks Data to arrange a meeting with Picard, not as Sub-Lieutenant Setal, but as Admiral Jarok, an esteemed Romulan officer who led a vicious campaign against Federation outposts. Jarok dismisses his notoriety as a waste of time, urging Picard to enter the Nelvana system. Picard refuses and gives Jarok an ultimatum: give the Federation the knowledge it needs to justify crossing the Neutral Zone, or end the investigation and damn him as a traitor. Realizing that Picard will stand his ground, Jarok gives Picard full cooperation, including tactical information on the Romulan fleet. With this knowledge, the Enterprise crosses the Neutral Zone to investigate Nelvana III.
Upon arrival, the crew discover that Nelvana III is devoid of any Romulan presence. Jarok is in disbelief and Picard suggests that the Romulans have been manipulating Jarok himself to test his loyalties. Before the Enterprise can leave, two Romulan Warbirds decloak and blockade their advance. When Romulan Commander Tomalak demands the return of Jarok, as well as the surrender of the Enterprise, Picard has Worf transmit a message from the Enterprise. Seconds later, three Klingon Birds of Prey de-cloak in a pincer formation around the Romulan Warbirds. It is revealed that Picard had previously asked Worf to request a partnership for this particular mission. The two Warbirds retreat, and the Enterprise heads back with the Klingons across the Neutral Zone.
With no possibility of ever returning home or seeing his family again, Jarok commits suicide. Commander Riker discovers a note that Jarok had left to his family, explaining his actions and the reasons for making his decision. Picard proclaims that if more men with the courage of Admiral Jarok step forward to make a change for the better, the day would come when they would be able to carry his message home.