After ten months without a break, T'Pol notes efficiency on board Enterprise is down, and suggests shore leave on Risa. Captain Archer agrees. En route, however, Archer receives a transmission from Admiral Forrest, informing him of a Vulcan Ambassador in need of extradition. With the closest Vulcan starship over a week away Enterprise is ordered to retrieve and deliver her to the Vulcan cruiser Sh'Raan.
Arriving at Mazar, Archer is informed by the High Council, that there is no need to send a shuttlepod as she is already on her way up. Archer and T'Pol are surprised to hear the Ambassador has been expelled for abuse of her position. Over dinner, V'Lar states she has no intention of defending herself against the criminal charges. T'Pol later tells Archer that the Ambassador has had a profound influence on her life; she is disappointed at her hero's sudden fall from grace. Archer is called to the bridge and speaks to a Mazarite captain who requests that V'Lar be returned for further questioning.
Archer stalls for time to contact Starfleet Command, but the Mazarite ship opens fire. The Enterprisespatial torpedoes have no effect, but the aft phase cannons disable the Mazarite ship's engines, allowing Enterprise to escape. Confronting V'Lar, Archer finds the Ambassador unwilling to reveal more, stating that it is a matter for Vulcan High Command only. Archer orders Ensign Mayweather to set a course to return to Mazar. En route, Archer again speaks to Admiral Forrest, who supports Archer's decision, but warns there may be diplomatic repercussions.
Later, after speaking with V'Lar in private, T'Pol persuades Archer to continue the rendezvous with the Sh'Raan, but Enterprise immediately comes under attack from three Mazarite ships. Outnumbered, Archer opts for flight and pushes Enterprise to her limits. However, even at Warp 4.9 the Mazarite ships still gain steadily. V'Lar suddenly asks to speak with Archer in private and confesses that her mission was to gather evidence against corrupt officials. Her reputation was intentionally sullied to make the Mazarites believe she would no longer be a credible witness. V'Lar offers to surrender herself for the safety of the crew, but Archer refuses and orders Warp 5.0.
Under attack, Enterprise takes a hit to its starboard nacelle and is forced out of warp. Stalling for time, Archer informs the Mazarites that V'Lar suffered injuries and is in critical condition. Allowing the Mazarites to board Enterprise, they fire their weapons into the stasis chamber holding V'Lar. The Sh'Raan arrives and threatens to destroy the Mazarite ships unless they surrender immediately. At this point, V'Lar reappears and Archer's ruse is exposed. A grateful V'Lar is seen off by Archer and T'Pol who tells them that she senses a bond of trust and friendship which bodes well for future human-Vulcan relations.