In her Ready Room, Tuvok and Janeway review the evidence and she shows Tuvok that she has found something Nimira overlooked. But when Tuvok draws to Nimira's attention the fact that Frane has a record of previous arrests for harbouring violent thoughts, Nimira counters by saying that he has been cured through previous engrammatic purging.
	In the Mari marketplace, an elderly Mari woman stops to buy from Talli's stall. Suddenly she experiences Torres' violent thought against Frane and stabs Talli to death.

Tuvok is puzzled by the two related attacks among these normally non-violent people and why the violent thought is still in circulation when Frane has already undergone an engrammatic purge. He mind-melds with Torres to learn more of the moment when Frane bumped into her. He learns that Guill probed her mind immediately afterwards.

Tuvok questions Guill who telepathically senses dark violent impulses in the recesses of the Vulcan's mind, and he offers to help Tuvok control them. They part but Tuvok follows him and witnesses Guill secretly accept money from another Mari. Tuvok deduces that Guill has a business interest in violent thoughts. He approaches Guill again, offering to telepathically exchange the violent images in his mind. Guill admits that he buys violent thoughts from people or sometimes takes them, as he did with Torres, and remarks that the crew of Voyager will make fine donors as they cannot control their thoughts. Guill denies he is responsible for the marketplace attack or for the circulation of Torres' thoughts leading to Talli's murder, but Tuvok starts to lead him to Nimira for questioning. At that moment two of Guill's fellow-conspirators intercept them and Tuvok is taken prisoner.

Torres resists uselessly as she is strapped into the chair and the procedure for the engrammatic purge commences. It is interrupted by Janeway contacting Nimira urgently to tell her that there is new evidence which proves Torres is not guilty.

Tuvok experiences some of Guill's violent images. Tuvok then seizes Guill in a forced mind-meld, promising Guill untold delights and a closeness he cannot experience except through the mind-meld. But instead Tuvok inflicts mental pain on Guill...

	...and Guill and Tuvok are beamed to Voyager, where Guill is detained.
	Nimira at first finds it hard to believe Tuvok's explanation that Guill and Frane were in collusion. Tuvok reveals a hitherto secret aspect of Mari society - the illegal trade in violent thoughts.
	After the Doctor gives Torres a clean bill of health, Tuvok says there are Vulcan methods he can teach her to help her control her temper. He says that, having experienced her thoughts, he has a respect for her already tight control over her violent Klingon nature.

Janeway's Ready Room. Seven: "You make contact with alien species without sufficient understanding of their nature. As a result, Voyager's directive to "seek out new civilisations" often ends in conflict." ..... Janeway: "What you call ignorance we call exploration. And sometimes it means taking a few risks. .... We seek out new races because we want to, not because we're following protocols. We have an insatiable curiosity about the universe."