The humanoid inhabitants of Atrea IV, who ask the Federation for help when the molten core of their planet begins to cool and solidify in Inheritance.
The Atreans are the people of Atrea IV, seen in the Next Generation episode Inheritance. In 2370 their scientists find that the planet's magma is hardening, which within little more than a year would end its geological activity and leave the world uninhabitable.
The Enterprise comes to assist two Atrean specialists, the geologist Pran Tainer and his human wife Juliana. The plan is to drill into pockets beneath the crust with the ship's phasers and reliquefy the core with plasma infusion units.
Juliana reveals that she was once married to Noonien Soong and helped to build Data. During the work Data discovers that she is herself an android, made by Soong to carry his dying wife's memories without her knowledge. Data decides not to tell her or her Atrean husband, and the mission succeeds.