Aliens abduct the ship's children to repopulate their dying world.
The legendary world of Aldea, long hidden behind a cloaking shield, suddenly reveals itself and invites the Enterprise to make contact. The Aldeans can no longer have children, and they abduct several children from the ship, including Wesley Crusher, offering trade in return. When Picard refuses, they use their powerful defences to push the Enterprise away.
On the planet Wesley leads the children in quiet resistance. Dr. Crusher, studying medical scans, finds that the Aldeans are suffering radiation poisoning caused by their own shield and the damage it has done to their ozone layer.
Riker and Data beam down past the shield and Wesley disables the controlling computer. The Aldeans accept treatment and give up their shield, and the children are returned to their families.