Harper has made some modifications to a slipfighter's automated navigation systems, and is testing them in a debris field. Dylan calls the tests a success, and tells Harper to bring the slipfighter back in, although Harper would like more time.

Andromeda detects high radiation levels in her ramscoop, but before she can do anything about it, a blue "mist" leaks into the Command Deck through one of the vents, and materializes into a sword-wielding Genite. The Genite knocks Beka's gun out of her hand, but Dylan fights it with his forcelance, taking the sword and killing the Genite – which "dissolves" into tiny blue "beads".

Andromeda informs Dylan that, while he was fighting the Genite, Tyr left the ship in Harper's modified slipfighter, and is maintaining communications silence. She is unable to track him, because Harper has also improved the slipfighter's ECM, so Andromeda is seeing eight slipfighters, all heading in different directions. She tells Dylan that, while Dylan was fighting the Genite, Tyr was in his quarters with privacy mode engaged, so Dylan tells her to override the privacy mode (which shocks Beka) to discover what Tyr was doing. They find that he had received a rather cryptic visual message from a woman.

With Andromeda's assistance, Harper examines the blue beads. He declares that the Genite was an "eidolon", a construct made out of dark matter – something that Harper was aware of in theory, but had never been able to create. Andromeda explains that the particles that made up the eidolon were small enough to get through her filters.

Andromeda attempts to determine where Tyr's message came from, based on the background of the image, which showed a barren, rocky planet. She has found a large number of possibilities, and suggests one particular system, which she says is a close match. Dylan instructs her to set a course for that system.

Beka wonders if this might be an elaborate trap for them – something to draw Tyr away, so they will follow.

Andromeda sounds an alert – there is a huge, 700-metre-tall Dylan floating in space ahead of them – clearly another eidolon. Dylan instructs Andromeda to move to intercept it, and the image disappears. Dylan speculates that someone is trying to divert them, and Andromeda notes that they are now headed towards the planet Elba 9, which is also a possible match. Dylan tells her to take them to Elba 9.

Andromeda detects that the eidolon particles have also infected her with a virus, interfering with her sensors, and allowing a man to come aboard. The man, identifying himself as Bartolome Naz, comes onto command on a powered wheelchair, and tells Dylan that he knows where Tyr is.

Tyr, meanwhile, has landed on a cold, rocky, desolate planet. After landing, he is attacked by another Genite with a sword. Just as the Genite is getting the better of the fight, it is shot from behind, by the woman from the message, and disintegrates into blue beads. The woman seems, at first, to be happy to see Tyr, but then slaps his the face and runs off. Tyr falls, surprised, then pursues.

Andromeda is unable to find any reliable information about Bartolome Naz – he has corrupted her database. However, Naz tells Dylan that he is a weapons designer, and that the woman in the message, Desiree Delene, was the love of his life, but she left him. In anger and jealousy, he hired Tyr to kill her. He thought that Tyr had done so, until he found the message from Desiree, and realized that Tyr had hidden her. He says that Tyr has gone to Desiree on a prison planet, Elba 9. Naz explains that he designed the defenses on Elba 9 – it is easy to land on the planet, but impossible to leave. Naz observes that he wants Desiree, and Dylan wants Tyr, so they should work together. He designed the defenses, and he figures that Andromeda is the only thing that has a chance to beat them. Dylan is less than thrilled with this plan.

On approach to Elba 9, Andromeda detects an asteroid, 5 kilometers long, in orbit, modified to serve as an automated mobile weapons platform. Naz claims that this "Atrox" cannot be beaten. The Atrox attacks, and Andromeda jumps to slipstream to get away.

Tyr is chasing Desiree, but he calls her "Medea". She asks him if he is trying to "finish the job", but he protests that he has not seen Naz in years. It becomes apparent that Tyr hid her to keep her safe from Naz, but she is angry with Tyr for leaving her. Tyr is obviously still in love with her, and says that she is "perfect". Desiree seems torn between caring for Tyr and anger with him. She does note the loss of his bone blades, saying it makes him just like her, but he protests that it does not make him like her at all.

Andromeda emerges from slipstream to find the Atrox following. They are surprised, but Naz tells them that the Atrox has a brain. Dylan orders Beka to take them into a close orbit of Elba 9, to hide from the Atrox, and take the Maru to find Tyr. Naz estimates that this will buy them about 3 hours. Beka and Harper take the Maru to the planet's surface.

Tyr and Desiree are talking in her home. She says that she sent the message a year ago, but much has changed since then. They kiss, but Desiree's security alarm goes off – she tells Tyr there are two intruders. They grab weapons and go to investigate.

As Beka and Harper approach Desiree's home, they split up, with Beka heading for the front, and Harper going around back. Desiree sees Harper approaching, and shoots at him. Tyr moves around behind him, but when he recognizes Harper, he relaxes. Beka sneaks up behind Desiree, but when Tyr sees Beka, he gestures to her that things are OK.

The four go into Desiree's house, and Beka and Harper tell them about Naz. Desiree is upset that they have brought Naz to her. Beka protests that they thought they were rescuing Tyr, but Tyr insists that he did not ask for help. Beka realizes that Tyr and Desiree are not enemies, so she contacts Dylan, who tells her to bring them up to the ship.

Andromeda tells Dylan that Naz's condition is easily treatable – he chooses not to walk. Dylan theorizes that this helps to feed his hatred. Naz, alone elsewhere in the ship, is assembling a weapon, muttering that he is looking forward to seeing Tyr.

Beka, Harper, Tyr and Desiree return to the Andromeda, where Naz ambushes Tyr, who was trailing behind, engaging him in a firefight. Naz catches sight of Desiree, which distracts him long enough for Tyr to shoot the weapon out of his hand as Beka and Harper rush back to investigate.

Tyr takes Desiree to her quarters, while Beka and Harper escort Naz to Dylan in Command.

Tyr insists, to Desiree, that he did not know that Naz was anywhere nearby, let alone on the Andromeda, but Desiree thinks he is still trying to collect his payment. Tyr claims he still loves her. Desiree says that untested love is worthless. Tyr, still calling her Medea, points out that he came back for her, and insists that his love was tested.

Beka and Dylan are analyzing the Atrox, while Naz is being guarded by Trance. They are also discussing what to do about Naz and Desiree.

Tyr arrives on Command. Beka reminds him that he told her, in very definite terms, that he could never be with a human woman. Tyr agrees that he did say that – to her.

Dylan concludes that their best plan for dealing with the Atrox is to get Naz to make an eidolon to protect them. Tyr presents this suggestion to Naz, saying it is his best chance to live. Naz says that assuming he even wants to live is a big assumption – despite his successes, he is still alone. He asks Tyr why he did not kill Desiree, but Tyr does not answer.

Desiree leaves her quarters, escorted by Beka, who notes that it would be safer for her to stay in her quarters. Desiree counters that it would have been even safer for her to stay on the planet, but that option was taken from her. Desiree tells Beka that her curse is to "be all things to all men", but Beka is unsympathetic. Desiree says that she considers her relationships with Naz and Tyr to both be failures. Beka seems to be getting suspicious of Desiree.

Harper and Naz are preparing the modified slipfighter for use against the Atrox. Desiree sneaks into the hangar and starts to look for a place from which she can shoot Naz. Beka comes running in, shouting that Desiree is an eidolon, and shoots her. Desiree falls to the ground – she is not an eidolon. Tyr rushes to her aid, and takes her to Medical, where he whispers to Trance that Desiree is, in fact, a Nietzschean.

While treating Desiree, Trance asks Naz: If he could get out of the chair, could he let Desiree go? Naz insists that the two issues are unrelated, but Trance is unconvinced.

The slipfighter is launched, with Tyr controlling it remotely. The Atrox ignores the fighter and continues to fire on the Andromeda. After the fighter negotiates closer to the Atrox (using Harper's improved navigation system), they activate the eidolon to make the slipfighter into a larger ship, which rams the Atrox. This disrupts the Atrox enough for the Andromeda to fire a full salvo of offensive weapons, destroying it.

In Medical, Desiree is recovering. Dylan asks Tyr if he is planning to leave with her, but Tyr says that he is not sure. Dylan insists that Naz must let Desiree go. Naz unplugs a wire connecting his chair to the medical systems, and shakily stands – he had agreed to Trance's treatment. He tells Desiree to go, and follow her heart. He will always love her, but she is free to go.

Tyr takes Desiree back to Elba 9. Tyr tells her that the two of them are "the greatest survivors". Desiree says that they will survive longer if they stay hidden, but Tyr protests that they will survive the longest if they have children, and he is willing to stay with her for that purpose. Desiree says that if Niobe, their matriarch, were alive, she would arrange it, but she is dead – Desiree is a Kodiak, Medea Cymri, out of Isabella, by Zarathustra, a childhood sweetheart of Tyr's, who has been living in hiding, pretending to be a human. She does not want to live "on the run", even for Tyr's sake. She is happy to stay on Elba 9, hidden, so Tyr leaves her there.