Subsurface Maintenance Grotto 6M430

Subsurface Maintenance Grotto 6M430 was an abandoned maintenance grotto carved into the side of an ice quarry on Biko's third moon of Seoba. It was in this chamber that Task Force Yama gathered roughly 300 insurrectionist prisoners to be loaded into a transport and taken back to Biko for processing.

The grotto consists of a cold and murky chamber with at least two exits. One is an airlock large enough to admit a. The other is an airlock in the grotto's access vestibule that leads through to the bottom of quarry pit. The airlock's interior crew chamber is large enough to comfortably hold twelve Spartan-IIs.

Battle of Seoba
When Task Force Yama arrived at Seoba on March 18, 2526, they discovered members of the United Rebel Front and its allied insurrectionist groups entrenched in the very same ice quarry that they had selected to be their base until the Covenant arrived to attack Biko. After a brief and intense battle, the UNSC captured the quarry, collecting the surrendered insurgents into the abandoned Subsurface Maintenance Grotto 6M430 to be loaded into the Banta-class transport Emmeline and taken to Biko to stand trial.

On March 19, a Covenant flotilla arrived in-system, forcing the task force to leap into action. Not wanting to send the Spartans into battle after discovering their distressingly young ages, Colonel Marmon Crowther of the 21st Space Assault Battalion assigned John-117 and his compatriots to guard the prisoners and load into the Emmeline. With ten minutes until the Covenant reached Seoba, the Spartans began directing the prisoners to board the transport via its loading ramp.

As the Spartans urged them up the ramp, John-117 noticed a group of insurgents trying to conceal the presence of one who was clearly a general. John knew that the Office of Naval Intelligence would want to interrogate ranking members of the United Rebel Front, so he ordered the line of prisoners to halt. Using his armor's onboard computer, he checked the identity of the individual, who turned out to be General Harper Garvin, and called him forward. After a failed attempt by Petora Zoyas to stall for him, Garvin complied. While the prisoners resumed boarding, Garvin attempted to work some details about the Spartans out of John, who was busy listening to Task Force Yama's command channel. In the process of launching to meet the Covenant threat, Captain Halima Ascot's prowler, the had been shot down, crashing into the quarry. Plasma bombardment began to shake the grotto, injuring some prisoners with falling chunks of ice. John ordered the rest to carry their wounded into the Emmeline, warning that anyone who delayed would die in the quarry.

Continuing to listen to the command channel, John could tell that Crowther would be unable to send any of his men to the Starry Night ' s crash site, and that he did not want to risk another prowler to investigate either. Not wanting to give up on Captain Ascot and her crew, or allow the Covenant access to a prowler, John decided that he and his teammates would instead go after the Starry Night. After telling Garvin to rejoin his people, he informed Emmeline ' s pilot that she and her flight crew would be leaving without them. When the pilot protested to launching without the Spartans to watch the prisoners, John rebuked her and reminded her to follow flight deck isolation protocols, which included depressurizing the troop bay if necessary. With that, the Spartans left the grotto and the transport launched shortly after.

List of appearances

 * Halo: Silent Storm