Countdown (Star Trek: Enterprise)  "Countdown" is the 23rd episode of the of the American science fiction television series "" and is the 76th overall episode. It first aired on May 19, 2004, on the UPN network within the United States. Set in the 22nd century, the series follows the adventures of the first Starfleet starship, "Enterprise", registration NX-01. Season three of "Enterprise" features an ongoing storyline that follows an attack on Earth by aliens called the Xindi, a group of aliens that did not appear in preceding series. In this episode, Captain Jonathan Archer (Scott Bakula) convinces the Xindi-Aquatics to aid him in his fight against the Xindi-Reptilians and Insectoids alliance to prevent Earth's destruction by their superweapon. In the midst of a battle between the two Xindi factions, an away team is sent to rescue Ensign Hoshi Sato (Linda Park), previously captured by the Reptilians. However, the superweapon departs for Earth, with Archer in pursuit on board a Xindi vessel. "Countdown" was the first collaboration between writers André Bormanis and Chris Black, and was directed by former "" actor Robert Duncan McNeill. It was shot over eight days, with additional sets built for the Xindi-Reptilian vessel and the interior of the superweapon. Critics praised the change in the dynamic between Major Hayes (Steven Culp) and Malcolm Reed (Dominic Keating). Roughly 3.5 million viewers watched "Countdown" on its first broadcast. Needing a third species' codes in order to arm the weapon, Ensign Hoshi Sato is injected with neural-parasites while she is a prisoner of the Xindi-Reptilians. With the Xindi superweapon about to be armed and time running out, Captain Jonathan Archer tries to persuade the Xindi-Aquatics to help destroy it. Sato's kidnapping, and Archer's promises to shut down the 70-plus known spheres, finally convinces the Aquatics into believing that the Sphere Builders, and not the humans, may indeed represent their true enemy. A battle between Archer's Xindi fleet and the Reptilian-Insectoid fleet soon breaks out around the superweapon. Locating Sato on board a Reptilian ship, a small squad of MACOs, led by Major Hayes and with the support of Lieutenant Malcolm Reed, transports on board the ship to extract her.