S1E17 · When the Bough Breaks

The Enterprise enters the Epsilon Mynos system, searching for the legendary world of Aldea. The planet de-cloaks, and reveals itself to the ship. The Aldeans beam down Commander William Riker (Jonathan Frakes), Counselor Deanna Troi (Marina Sirtis), and Chief Medical Officer Beverly Crusher (Gates McFadden) to the planet. The Aldeans explain that they have been unable to bear children for many years and revealed themselves to the Enterprise in hopes they could trade their advanced technology for some of the Enterprise ' s children so that they can re-populate their world.

Riker refuses and the crew is returned to the Enterprise. Simultaneously, seven children, including Wesley Crusher (Wil Wheaton), are taken down to the planet protected by a planetary energy shield that the crew of the Enterprise are unable to penetrate. While the Aldean elders attempt to integrate the children into their society, Wesley is shown the "Custodian", an ancient computer system that the Aldeans rely on but do not understand.

As Captain Jean-Luc Picard (Patrick Stewart) attempts to negotiate with the Aldeans, they briefly allow Dr. Crusher to reunite with her son on the planet. Wesley hints about the Custodian to her, while she secretly passes him a tricorder to scan the Aldeans. After Picard fails to get the Aldeans to agree to the children's return, they fire an energy weapon that sends the Enterprise three days away from Aldea at maximum warp. The Aldeans warn that they can send the Enterprise an impossibly far distance if they refuse to cooperate. During the return trip, Dr. Crusher reviews the scanner results and finds the Aldeans are suffering from radiation poisoning, which has harmed their reproductive capabilities but can be reversed if the source is discovered. On arrival back at the planet, Picard orders the crew to try to find a way through the planet's shield while he restarts negotiations.

Wesley, aware the Enterprise is in orbit, arranges for the children to passively resist. When the Aldeans request Picard's help to resolve the issue with the children, the crew finds a way to beam through the shield, allowing Commander Riker and Lt. Commander Data (Brent Spiner) to sneak onto the planet. Data manages to disable the Custodian, disrupting the Aldean's transporter and planetary shield. Dr. Crusher explains to the Aldeans that their shield has weakened the ozone layer of their planet, exposing the inhabitants to ultraviolet radiation that has left them unable to bear children.

The radiation would likely have the same effects on the children from the Enterprise. Without the planetary shield, the ozone layer will naturally return, allowing the Aldeans to reproduce again. The Aldeans accept the error of their ways and return the children to the Enterprise. Starfleet offers to help to correct their ancient systems and recognize that they will have to forgo their invisibility to continue their society.