Guinan visits Beverly in her quarters, only to find her packing her belongings. She has been relieved of her duties, and has been summoned back to Earth to face a formal inquiry — and the beginning of the end of her Starfleet career ...

Beverly invited a group of experts aboard the U.S.S. Enterprise to hear Doctor Reyga, a Ferengi scientist, explain how he had invented a metaphasic shield designed to protect a shuttle and its occupants from the destructive forces of a star's corona. To that end, one of the Enterprise shuttles was outfitted with the shield, so that Reyga himself could fly it into the corona of the star Vaytan. The Klingon expert, Kurak, preferred that someone more objective fly the shuttle. The Takaran scientist, Jo'Bril, volunteered, to which Kurak and the other two experts present, a Vulcan named Dr. T'Pan and her human husband, Dr. Christopher, agreed.

As Dr. Reyga flew the shuttle into the star's corona, Data detected an increased level of baryon particles in the shuttle cabin. In trouble, Jo'Bril managed to alter the shuttle's course back out of the corona before slumping unconscious. He was beamed directly to Sickbay, but Beverly was too late to save his life.

Beverly and Nurse Ogawa were baffled after examining Jo'Bril's body — they couldn't determine the cause of death. Later, she talked with Geordi, Reyga, and Data, who were examining the shuttle. Geordi determined that minor hull damage confirmed baryon particles did get through, but that wasn't necessarily the cause of death. Geordi suggested that there must have been something in the corona that Reyga never anticipated. The implication made the Ferengi angry. Unfortunately, though, Beverly was forced to ban further tests — even if Reyga himself was the pilot. He vowed to prove himself.

When Beverly saw Reyga again, he was dead. The evidence suggested suicide, but she refused to believe that. Picard, however, told her that Reyga's family wouldn't allow an autopsy before they performed Ferengi death rituals. Beverly was certain it was murder, and the most likely suspects were the other three scientists — the ones most likely to gain from his death. The Klingon told Beverly that an argument stemmed from Reyga's accusation of sabotage — which Kurak denied. Then, with no other clues, Beverly went against orders and performed an autopsy. Not surprisingly, the Ferengi government lodged a formal complaint with Starfleet, who forced Picard to relieve her of duty.

Guinan encourages Beverly to find the murderer. Beverly and Data discuss sabotage possibilities, they do an autopsy and find the traces, but it's still not proof. The bridge crew notes that the shuttle equipped with the metaphasic shield has suddenly been launched. Picard is shocked to see it is Beverly, ready to risk it all for the test of a theory.

The bridge officers are shocked to see Beverly has set a course for the star's corona. Despite Picard's protests, she reaches her destination. The shield functions perfectly — Reyga was successful. Suddenly, the Enterprise loses contact with the shuttle. The reason: Jo'Bril is aboard with Beverly, very much alive, and pointing a phaser at her. He has disconnected communications, and tells the shocked doctor that he put himself into a state of physiostasis, a talent unique to his race, which allowed him to fake death. He was hoping to just discredit Reyga and his invention — but now he has more than he bargained for, because he now has the shuttle, which he plans to develop into a weapon. Beverly suddenly makes the shuttle rock violently, and they scramble for the loose phaser. She gets to it first and vaporizes Jo'Bril, then sets course back to the Enterprise. The mystery has been solved, and she has been reinstated.