Catherine/Spartan Mountain

Spartan Mountain is the third chapter of Spartan Ops ' third episode, Catherine.

Summary
Commander Sarah Palmer sends Fireteam Crimson on a rescue operation for Mountain Squad, a science attaché who were shot down by Covenant forces during their mission to locate a "mysterious" signal discovered by Galileo Base. Crimson is brought near the crash-site by Pelican transport and are told to "double-time" it towards Mountain's position. Shortly after landing, Crimson's communication with Palmer is jammed by Covenant jamming equipment. Crimson arrives to Mountain's crash-site and are met by a team of Spartan-IV survivors who are fending off a Covenant attack. After securing the immediate area, Spartan Fredric Zurenia of Mountain Squad points to a pair of Covenant jammers behind a large shield. As Mountain regroups to attack, Crimson disables the shield system protecting the jamming equipment. While attacking the equipment, Covenant reinforcements arrive via in large Orbital drop pods. After destroying the communication jammers and clearing the area, Crimson is finally contacted by Commander Palmer.

They are told to assist the survivors of Mountain Squad in completing their mission. Palmer points them to a Forerunner tower on the other side of the canyon, where Infinity Science wants them to investigate it. While proceeding to the objective, several Phantom dropships arrive with more Covenant reinforcements. After disabling the tower's shields, multiple Kig-Yar Storm units emerge from within the tower, led by Sangheili Zealots and Warriors. They attack the Spartans, but are quickly eliminated. With the tower and its vicinity secured Dr. Halsey comes online. She marks a point of interest inside the tower and tells Crimson to go near it. Halsey theorizes that the tower's location could be the source of the signal Mountain was looking for or the signal's destination. She tells one of the Spartans to activate it in order to find out.

Immediately after activating the device, the tower emits a large energy beam into the sky, which Halsey assumes is navigation data for Requiem. Jared Miller then tells Palmer that a large Covenant force is inbound towards Crimson's position. During the attack, the rest of Mountain Squad are killed, leaving Crimson alone to finish their job. Commander Palmer orders Crimson to fall back to Mountain's crashed Pelican in order to stock up on whatever ammunition and supplies while Robert Dalton arranges an extraction.