Data defends a robot's right to survive.
Dr. Farallon is testing a mining tool called the exocomp, a small robot that appears to show signs of self-preservation. Data believes that these devices may be alive and deserve rights, while Farallon thinks they are just machines. When an emergency endangers the ship, the exocomps are needed for a rescue.
The episode is a thoughtful examination of artificial life, and it echoes the themes of the earlier Data stories. Picard has to decide whether to risk the exocomps for the sake of the crew. Data's loyalty to the little machines is a highlight of the story. It is a quiet but meaningful episode about what it means to be alive.