Terraformers on Velara III uncover a form of intelligent life.
The Enterprise checks on a terraforming team on Velara III after losing contact with them, and finds that an engineer has been killed by a laser drill. Data is nearly killed by the same equipment, and the crew grows suspicious of the project's leaders.
A small sparkling object brought up from the surface turns out to be a crystalline life form that thrives in the thin layer of water beneath the sand. The terraforming work has been destroying it, and it has been fighting back. Once aboard, it grows stronger and takes control of the ship's systems.
The life form dismisses humans as mostly water in a scornful phrase that became well known. Picard negotiates a truce, it is returned to the surface, and the colonists agree to leave the planet alone.