When the entire crew is rendered unconscious, a quartet of large-eared, bickering thieves invades Enterprise. These plunderers, the Ferengi, are determined to make off with everything that's not bolted down. Meanwhile, Trip awakens after a long stint in the decon chamber and senses that something's not right on the ship. After spotting the thieves in action, Trip does his best to stay hidden and formulate a plan.
The Ferengi awaken Archer by using a hypospray, and proceed to interrogate him about the location of the ship's vault. Quickly ascertaining that the Ferengi's primary emotion is greed, Archer uses this against them while trying to stall for time. Unwilling to strike a deal with Archer, the Ferengi leader, Ulis, takes two of his crew with him to search for the elusive vault, leaving his cowardly cousin, Krem, to watch over Archer and load the stolen goods onto the Ferengi ship. Using the power of suggestion, Archer cautiously plants a seed in Krem's mind — perhaps he should stop taking orders from his cousin and start thinking for himself. Krem ponders this as he shackles Archer to the wall and goes off to get the captain some food and water. Seizing the opportunity, Trip, who has been watching the whole time, goes to Archer and attempts to free him. He is unable to get the shackles off, but Archer has enough time to outline a plan for escape.
Trip heads off to Launch Bay Two, where he finds the hypospray the Ferengi used to resuscitate Archer. He manages to wake T'Pol, but there isn't enough vaccine left to revive anyone else. After Trip explains the situation to her, T'Pol ascertains that an artifact Trip brought back from a recent lunar survey must have been placed there intentionally — it released some kind of gas when she opened it, knocking out the crew. Moving out of sight, T'Pol keeps an eye on the Ferengi intruders via a monitor, while Trip mysteriously places a mag-lock on the Bio-Matter Resequencing hatch. Meanwhile, tensions are running high among the thieves. As they bicker, T'Pol sets off several alarms, causing the Ferengi to become extremely agitated and suspicious of everything and everyone ... including each other. Satisfied, T'Pol moves out to regroup with Trip. Trip, however, is spotted by one of the Ferengi and captured.
The thieves take Trip to Launch Bay Two, where he is reunited with Archer. The two men pretend to be at odds, playing off of one another as if they are greedy Ferengi themselves. Eventually, Trip strikes a deal with Ulis, and convinces the Ferengi to allow him to lead the thieves to the vault. With three of the Ferengi off with Trip, Archer is left to deal with Krem. Faking a back injury, Archer convinces Krem to continue loading the cargo onto Ulis' ship himself. When he gets to the Ferengi bridge, Krem is surprised to find T'Pol waiting for him — she claims to be a prisoner of the humans, and begs Krem to take her away. Using her feminine charms to soothe Krem, T'Pol expertly performs the Ferengi technique known as "oo-mox" ... and then applies an effective nerve pinch, rendering Krem unconscious. After arming herself with a phase pistol, T'Pol moves out quickly. Meanwhile, Trip has led the Ferengi to the Enterprise "vault" — the Bio-Matter Resequencing hatch, equipped with the mag-lock. The greedy Ferengi all jump into the "vault" at once, not trusting each other with the "treasure." Once inside the chamber, they find nothing but an empty room ... until T'Pol jumps out from her hiding place and takes out all three of them with her phase pistol.
Later, the Enterprise crew is revived, and the Ferengi thieves are forced to put back all of the stolen equipment. Though the crew hasn't learned much about this mysterious alien race — not even their name or where they come from — Archer warns them never to approach a Starfleet vessel again. He does, however, give Krem a chance to prove himself — the Ferengi takes command of Ulis' ship and heads out with his fellow thieves in shackles.