While en route to the Berengarius system to scout prospective sites for Starfleet‘s first starbase on the system’s seventh planet, Enterprise is intercepted by an Orion Syndicate vessel. Archer goes to tactical alert and hails him, seeing the captain, Harrad-Sar. He demands Archer power down his weapons immediately, or he’ll attack.
Archer suggests they deactivate their weapons together, and Harrad-Sar agrees. He then offers a business proposal, inviting Captain Archer aboard his vessel in the name of “smoothing relations” between their peoples. Archer decides to accept and, with an away team, heads to the transporter. Along the way, Lieutenant Reed expresses his misgivings, given that their last unfortunate encounter with the Orions nearly turned nine Enterprise crewmembers into slaves. Archer tells him it is worth the risk just for the possibility of establishing diplomatic relations with the Syndicate and Starfleet, “to have one less hostile species out there.“
In engineering, Commander Tucker is treated brusquely by Kelby, who feels that his promotion to chief engineer may be threatened by Tucker’s continued presence. Tucker assures him it’s only temporary and he will go back to the Columbia NX-02. T’Pol volunteers her services to help with the engines. During, she asks Tucker if he has been experiencing intense daydreams. He jokes around and says no. He asks her if she is going to tell him what this is all about but she refuses.
On the Orion ship, Harrad-Sar begins with small talk, pouring some Meridor that Harrad-Sar obtained from the Gorn Hegemony. “The less said about them, the better“, the Orion man states. He also mentions Archer’s reputation. When Archer asks Harrad-Sar what he had wanted to discuss with him, the Orion tells him that is poor custom to discuss business “before entertainment. If the food didn’t arouse your hunger, this should.” Soon, three Orion slave girls emerge, who dance, scantily-clad, in front of the mesmerized Enterprise crewmates.
Afterward, Harrad-Sar offers Archer the coordinates of a planet rich in magnesite; he proposes to broker a deal between Starfleet and the Syndicate for mining operations. As a token gesture of good will, he gives Archer the three slave girls – Navaar, D’Nesh and Maras.
Meanwhile, Reed shows the Orions to quarters. Taken by them, he has a little trouble answering their questions about the ship and the location of Archer’s quarters. He leads Navaar to quarters, first, and, awkwardly leaves her to see the other two.
As Enterprise travels to the coordinates to examine the planet, T’Pol reports numerous disruptions due to the presence of the women; she also reminds Archer of Starfleet’s official stance on slavery. The crewmembers seem obviously distracted by the three very seductive women: the men begin competing with one another and exhibit aggressive behavior, while female crew-members experience intense headaches. Reed and Ensign Travis Mayweather discuss the recent arrival of the Orion women while working out in the ship’s gymnasium. Mayweather recalls when he was fifteen years old, the ECS Horizon picked up some Deltan women whose ship was having engine trouble. He recalls that they “were very open.” The only thing that helped him get through it was weight training with his father, as the pain of working out took the images of the females out of his mind. Reed decides to take his advice, but Mayweather suggests he use bigger weights.
Later, Ensign Hoshi Sato enters sickbay and asks for a treatment for a headache she’s having. Dr. Phlox can detect nothing wrong with her – just as he did for Ensign Keeley, a fellow female officer, a few minutes prior. Oddly, Phlox nearly falls to the floor while preparing a medication for Sato. He notes that he seems to be nearing a new sleep cycle even though he just finished one recently, as Sato points out.
Numerous skirmishes and challenges to authority are also observed. Navaar then works her way closer and closer to the captain, while D’Nesh has chosen Kelby as the object of her affections and manipulations. D’Nesh goes to engineering and gets Kelby to show her around engineering. Kelby initially hesitates, but then does so, and neglects his duties as well. Tucker soon sees this and takes him aside to reprimand him, however, he refuses to comply and defies him, noting his existing concerns with Tucker’s role over him. Tucker has to order him to quarters or to the brig. He finally backs down, in full view of D’Nesh.
Navaar, getting a visit from the captain, is told that she and her sisters are guests, not slaves, but she says she can’t imagine any other life other than slavery. Calling him an honest man, she says even though Archer doesn’t wish to own her, she still wants to please him. They kiss, but are interrupted by the Enterprise arriving at the planet.
Archer gets to the bridge, having left Navaar reluctantly. T’Pol states that, as promised, they detect significant amounts of magnesite. Archer appears unsteady on the bridge as he orders scans to find out how much. A small ship is soon detected and, with minimal weapons, fires on them. T’Pol says they’re probably a science vessel and Reed says it’s impossible for the small ship to damage Enterprise even if they keep continuously firing on the Starfleet vessel. Archer, shockingly, orders the phase cannons to fire and destroy the vessel, but Reed refuses the order. Archer tries to push him away to do it himself, but just then the ship moves off unharmed.
Meanwhile, D’Nesh has found Kelby’s quarters and visits him.
Kelby and D’Nesh are in bed in the engineer’s quarters talking, Kelby complaining about Tucker and thinking he’s better than him. D’Nesh provokes his feelings by agreeing with him. When he tries to end the conversation, D’Nesh starts to leave, saying Kelby doesn’t know what he wants. He says he will do anything to keep her there. They lay back in bed and passionately kiss.
Kelby covertly enters engineering and quickly makes his way to an engineering console on the upper level. While Tucker is operating controls on the warp core, an alarm goes off and he finds Kelby above him, sabotaging the EPS system. Tucker and Kelby engage in a fistfight and Tucker eventually subdues him, but the system is severely damaged.
In sickbay, Doctor Phlox reveals that Kelby is suffering from escalated levels of adrenaline, brought on by pheromones from the Orion slave girls. These pheromones are accelerating the crew’s metabolism, causing aggression and delusional behavior among men and headaches and discomfort among women to divert competition; Phlox himself has been affected, he says, forcing him to rely on stimulants to counter his interrupted sleep cycle. Only Tucker and T’Pol appear to be immune. Phlox says for everyone else, the longer they’re exposed, the worse the effects will be.
The slave girls are imprisoned in the decon chamber, and a search of their quarters turns up a communications device, which they have been using to speak with Harrad-Sar. Archer confronts them, and Navaar nearly convinces him to release them, but T’Pol brings the captain to his senses. The Orion women continue to deny everything.
T’Pol wants to go back to the bridge to keep an eye on Archer, but he orders her to Engineering to help Trip work on the repairs. T’Pol tells Tucker that there have been altercations throughout the ship, and she is worried about the Captain. Tucker says he can’t figure out why he is the only male on the ship to be unaffected by the pheromone. T’Pol says that since Tucker and T’Pol have “mated“, he is bound psychically to her, and thus he enjoys the immunity granted by her Vulcan physiology.
With Enterprise‘s engines disabled, Harrad-Sar returns. Archer hails him and defiantly says their weapons are still functional. Harrad-Sar isn’t concerned, saying the Syndicate has put a reward on Archer’s head, dead or alive – and they don’t care if it is still attached to his body.
He is ready to claim his reward – the Enterprise and Captain Archer. After a brief battle, the Orion vessel knocks out the Enterprise’s weapon systems, including both fore and aft phase cannons. The Orion ship hooks Enterprise and begins towing her away. He hails again, and Harrad-Sar then reveals that he himself is the slave – a slave to the Orion females on Archer’s ship.
T’Pol and Tucker have a plan to release the Enterprise, and Archer tells her to try it. She just has to wait on Tucker’s final adjustments. Just then, having convinced their guards to let them escape, the Orion females now emerge from the turbolift onto the bridge. D’Nesh begins fondling Reed while Navaar talks to the Captain. Navaar persuades Captain Archer to have T’Pol arrested, saying she is just jealous; Archer complies and orders Lieutenant Reed to arrest the Vulcan. Hoshi protests but the men ignore her. Reed draws his phase-pistol and begins to carry out the order, but is stunned unconscious by Commander Tucker, who also stuns Archer and Ensign Mayweather. He signals T’Pol, who uses the ship’s deflector to send a positron burst through the grappling line to Harrad-Sar’s ship, disabling it and releasing the grappler. The Orion females, after one final (failed) attempt to woo Tucker, are escorted off the bridge by phase-pistol and are later sent back to their ship.
Phlox begins treating the affected crew, who are slowly starting to recover. The after-effects will last for a few days. T’Pol makes a joke, and Archer says she seems to be picking up some of Trip’s bad habits. As Enterprise warps away to continue its mission, T’Pol and Tucker walk down the corridor together. He says Captain Hernandez must want her Chief Engineer back on the Columbia, and T’Pol says there are still repairs to make on Enterprise. T’Pol asks him to remain on board as part of their crew to benefit the Enterprise. He asks if she wants him to stay for personal reasons and she says she doesn’t understand. Angry, he turns to leave, but T’Pol pursues him, and says she does want him to come back. He says he’ll think about it, and starts to walk away again. T’Pol grabs him and kisses him. Tucker agrees to stay, and reveals that he had actually made an official request to transfer back to Enterprise three days earlier.