A human invades the Taelon Commonality, prompting Da'an and Zo'or to visit a psychic conference to try to find the culprit. A Russian psychic named Katya Petrenko warns Zo'or to change his approach to humanity lest it leads to the downfall of both races. She then befriends Boone and reveals that she knows about his true allegiances. Sandoval hires Judson Corr, the man who killed Boone's wife, to assassinate Katya on Zo'or's orders. Augur sends Madame Marie, a psychic he knows, to test Katya. Marie confirms that Katya is the genuine article. Katya invites Boone to the Resistance base, which she has found on her own. Da'an, Zo'or, and Quo'on question Katya, but she denies being the invader. At the conference, Corr releases a toxin targeting Katya's DNA. Boone rushes her to Dr. Belman's office, where they use a special device to perform a Mental Fusion, allowing Boone to see Katya's memories and thoughts. He learns that humans have psychic powers thanks to Ma'el. Katya succumbs to the toxin and dies. Da'an decides to keep the knowledge of Ma'el's actions from the Synod.
- Abusive Parents: Lili's father used to beat her brother.
- The Collector: Augur reveals to Lily that he collects original paintings, frequently stolen by others.
- Electronic Telepathy: Dr. Belman wants to allow Katya to transfer her thoughts and memories to Boone with a direct connection.
- Foreseeing My Death: Katya senses that her time is coming to an end, predicting her assassination. She senses that Sandoval's involvement.
- Gratuitous Russian: Katya greets the conference in Russian, before switching to English. The Russian is surprisingly good.
- Hive Mind: The Taelons are disturbed by a human presence in the Commonality, seeing it as a threat to them. They believe that Katya Petrenko is the one doing it. Katya denies it, claiming to have never entered into any such psychic network.
- Improbable Aiming Skills: At a gun range, Corr uses two guns to draw an almost perfect heart on a target.
- Professional Killer: Sandoval once again makes use of Judson Corr's services to kill someone. Corr is reluctant to work with Sandoval again, especially if Boone is involved, but Sandoval doesn't leave him any choice. Boone recognizes Corr, despite his disguise, moments after he triggers the toxin, hitting him with a Skrill blast and allowing the cops to grab him. Boone realizes that Sandoval has to be involved, and he wouldn't act without Taelon orders, leading him to correctly suspect Zo'or.
- Psychic Powers: Psychics are more universally accepted and their abilities largely proven. It's eventually revealed that humans have them thanks to Ma'el, who wanted humans to have the ability to better communicate with the Taelons and work together as equals.
- Skeptic No Longer: Lili is the only one to be skeptical about psychics. Everyone else accepts their existence as a given, even Doors. Madame Marie helps to turn Lili around.
- Synthetic Plague: Corr takes a sample of Katya's DNA and uses it to synthetize a toxin keyed specifically to her, since Sandoval gave him specific instructions that no one else is to be harmed.
