Following a routine mission at the Tanuga IV science station, Riker beams back to the U.S.S. Enterprise moments before Dr. Apgar, the director of the Starfleet research facility, is killed in an explosion. A short time later, Chief Investigator Krag of the Tanugan security force arrives to take Riker into custody after Apgar's widow, Manua, and his assistant Tanya accuse the first officer of threatening Apgar. Picard, however, refuses to release Riker until reasonable evidence is offered to warrant his arrest.

Programmed with the testimonies of Riker, Manua, Tanya and the information in Apgar's personal journal, the holodeck recreates the events leading up to the fatal explosion, according to each person's perspective. Contrary to Riker's claims, the accounts of the other witnesses indicate that he had tried to seduce Manua and intimidate Apgar. Although Picard does not believe the accounts, he admits that the corroborating testimonies provide Krag with enough evidence for Riker's extradition.

Meanwhile, Geordi, Data and Wesley try to determine the cause of a power drain which occurred as Riker was being transported off the station, as well as the source of the energy blast which cause the explosion. Krag's evidence shows that the energy source came from Riker's position as he was beaming out, which means he could have fired his phaser at Apgar as he was departing.

In their investigation, however, the Science Team finds out that Apgar had discovered the new source of energy which Starfleet requested, but hid that fact so that he could develop it into a weapon that he would sell, at great personal profit, to the highest bidder. Using a holodeck recreation, Picard asserts that Apgar was afraid Riker would tell Starfleet that his work was completed before the scientist could create the valuable weapon.

Geordi is then able to prove that Apgar had intended a beam from his energy source to interfere with Riker's transport, scattering his cells through space and killing him in what would appear to be an accident. However, the beam merely reflected off the transport effect back into the condenser, causing the explosion and Apgar's subsequent death. Convinced by the crew's evidence, Krag drops all charges against Riker.