The crew of the Enterprise encounters Skalaar, a Tellarite who abruptly offers to give them a tour of a nearby planet. Unfortunately, Skalaar is actually a bounty hunter who kidnaps Captain Archer, planning to turn him over to the Klingons for payment. The Klingons have apparently placed a substantial price on Archer's head since his escape from Rura Penthe. Archer soon learns that Skalaar plans on using the reward to buy back Tezra, his previous ship.
On Enterprise, Sub-Commander T'Pol and Doctor Phlox undergo decontamination after a recent away mission. T'Pol begins acting strangely, and begins making sexual overtures to Phlox. It appears that a microbe has activated pon farr, the Vulcan sex drive. Phlox races to find a treatment, but T'Pol's actions become more and more erratic. Finally, she knocks Phlox out and escapes from decontamination. Luckily, Lieutenant Reed and a security team manage to subdue her. Later, T'Pol wakes up feeling more or less her usual self, and embarrassed by her actions, Phlox promises not to mention what happened to anyone.
Meanwhile, Skalaar runs into trouble when a rival bounty hunter tracks him down and demands that he turn over Archer. Skalaar refuses, and the rival opens fire. In the battle, Archer convinces Skalaar to temporarily free him, and the two men land on a nearby planet to make repairs. As they work, Archer learns more about Skalaar's circumstances. Skalaar turns Archer over to the Klingons as planned, but ends up receiving only two-thirds of the promised reward. In revenge, he alerts Enterprise to the location of the Klingon ship, and Archer escapes in an escape pod. Enterprise arrives and retrieves Archer, damaging the Klingon ship enough to end the battle. Some time later, Skalaar contacts Archer and warns that the price on Archer's head will probably double. Grateful, Archer bids Skalaar farewell.