"Divergence" is the sixteenth episode of the fourth season of the American science fiction television series Star Trek: Enterprise. It originally aired on February 25, 2005 in the United States on UPN. It was the fourth episode of Enterprise to be written by Judith and Garfield Reeves-Stevens, and was the first episode of a Star Trek series directed by David Barrett. "Divergence" is the second part of a two part story, following on from "Affliction". Set in the 22nd century, the series follows the adventures of the first Starfleet starship Enterprise, registration NX-01. In this episode, Columbia arrives so that Commander Tucker can be transferred to conduct repairs on Enterprises warp engine before it overloads. The two ships then pursue a lead to a Klingon research outpost where Phlox is under pressure to cure the virus that the Klingons created from augmented human DNA. Filming took eight days, with a two-week seasonal hiatus towards the end of December. In addition to the guest stars who appeared in "Affliction", they were joined by Wayne Grace as Admiral Krell. The episode received Nielsen ratings of 1.7/3 percent, which were lower than the previous week's episode. The critical response was mixed, the concept was praised but there was criticism over the plot holes and characterisation. The two part story has been named as one of the best storylines seen in Enterprise. Plot With the ship unable to decrease speed below warp 5, and the warp core reaching dangerous levels, Columbia and Commander Tucker rendezvous to provide assistance. However the crew realise that the transporter cannot be used at warp, so the ships will need to maneuver in close proximity in order for Tucker to be transferred. Captain Archer releases Lieutenant Reed from the brig to perform the transfer. Once on Enterprise, Tucker successfully performs a rapid non-standard cold boot on the warp engine, which purges the Klingon subroutines. Tucker then agrees to remain onboard temporarily to assist with repairs. Meanwhile, physician Antaak and a badly beaten Doctor Phlox update General K'Vagh on their progress. K'Vagh contacts Admiral Krell, who tells him that if a cure is not completed soon, the facility will be eradicated in order to contain the disease. Back on Enterprise, Archer questions Reed about his recent actions, and is contacted by Harris from Section 31, a secretive agency within Starfleet. Harris reveals that Phlox is on an important mission and