Operation: WHISTLE STOP

The mission to Ven III was an operation on the surface of Ven III in the Ven system on May 8, 2558, conducted by the United Nations Space Command to recover a bioweapon from the hands of a Sangheili and numerous Kig-Yar pirates, slavers, and smugglers.

Prelude
On May 8, 2558, a United Nations Space Command spy drone was sent to investigate the barren surface of the unclaimed planet Ven III—located at the borders of the Joint Occupation Zone—after a group of Kig-Yar settled on the planet and were operating in an old Covenant research laboratory. While scouting out the planet, the drone discovered the diseased corpses of the Kig-Yar inside the laboratory and an unidentified Sangheili Storm that had left the laboratory holding a canister several hours earlier. Admiral Serin Osman, Commander-in-Chief of the Office of Naval Intelligence, was alerted of the discovery. The Kig-Yar were discovered to have been killed by an unknown biological agent they were manufacturing within the laboratory and ONI believed that the Sangheili may be an agent of Jul 'Mdama and may have double-crossed the Kig-Yar in the lab, or that they released the bioweapon on themselves by accident. Admiral Osman contacted Captain Thomas Lasky aboard and debriefed him on the situation. Osman ordered Lasky to deal with the situation and that Lasky must contain the situation while exercising extreme caution before the Sangheili can use the bioweapon can be used against humanity. Lasky hand-picked a team of two SPARTAN-IVs, Naiya Ray and Gabriel Thorne. Due to the nature of the mission, Lasky decided that he must use the smallest team possible out of risk of alerting the target Sangheili to the threat and losing him in Ven III's extensive tunnel systems. After being debriefed, the two Spartans were sent to Ven III.

The mission
The two Spartans were deployed to Ven III's surface by a. As Ray and Thorne made their way on the planet's surface, they encountered a number of wandering Kig-Yar but no organized resistance. The two entered a narrow canyon where they lost communications with Infinity due to a nearby jamming field. As the Spartans proceeded further into the canyon, they were observed by the Sangheili, who had just destroyed the UNSC spy drone that was delivering the feed to Infinity. Infinity ' s shipboard artificial intelligence, Roland, immediately alerted Lasky to this as well as the communications blackout, suggesting for Infinity to change course toward Ven III to provide backup for the ground team. Having been ordered to avoid direct engagement, Lasky instead had Roland summon Commander Sarah Palmer. Meanwhile, Thorne and Ray observed a Covenant structure for some time before entering it. Once they were inside, the two SPARTAN-IVs were ambushed by the Sangheili and a contingent of Kig-Yar. As a skirmish ensured, the Spartans were able to defeat most of the Kig-Yar with the help of their armor-integrated thrusters. However, the Sangheili attached a shock device onto Thorne's armor and activated it. The electronic shock knocked Thorne unconscious and the Sangheili captured him. Escaping on a Type-32 Ghost with Thorne, Spartan Ray quickly followed.

Meanwhile, aboard Infinity, Captain Lasky proposed sending another two-man Spartan team to backup Thorne and Ray. However, Commander Palmer insisted on the deployment of a entire SPARTAN-IV fireteam. As Ray continued to chase after the Sangheili, they eventually moved out of the range of the communications jammer, allowing Ray to contact Infinity. Ray followed the Sangheili and Thorne into a deep subterranean tunnel where she discovered an enormous cavern filled with former Covenant vessels and vehicles; a major hideout for Kig-Yar pirates. Although the UNSC originally estimated there to only be around a hundred Kig-Yar on the planet, Ray realized that there was at least two hundred thousand of them. Noticing Kig-Yar smugglers, black market arms dealers, slavers, and pirates operating with in the cavern, she saw the Sangheili and a Kig-Yar carrying Thorne's unconscious body into a hangar bay. However, a Kig-Yar snuck up behind Ray and ambushed her. As her signal with Infinity terminated, Lasky ordered Roland to carry out the course change towards Ven III and to call for all teams on deck.