Dr. Crusher investigates a colleague's death.
Dr. Crusher is determined to find out why a respected scientist died in a test of a new technology, and she begins to investigate. She is warned off by her superiors, and she is forced to question her friends and colleagues. The story is told in flashback, as she describes the events to Guinan, who listens.
The episode is a murder mystery with a touch of science fiction. Dr. Crusher takes on a role that is more like a detective than a physician, and she has to make a difficult choice. It is a rare story that gives the ship's doctor the lead, and its structure is a clever touch. It is a solid, suspenseful hour.