SUMMARY
The Battle of Aktis IV was a conflict between the UNSC forces aboard the Infinity and the Covenant forces under command of Jul 'Mdama on the planet of Aktis IV in July 2558. Immediately following the Battle of Oban, the UNSC Infinity attempted to jump to slipspace, but quickly realized they were stuck. Unbeknownst to them, Dr. Halsey and Jul 'Mdama had used a Forerunner artifact to take control of the Infinity's slipspace drive, which was Forerunner in origin. Forces from the Infinity were sent to a nearby planet, Aktis IV, with the Infinity's half of the Janus Key to investigate some anomalous readings and try and fix the slipspace drive issue. The plan was a ruse by Jul 'Mdama to get to the UNSC's half of the Janus Key, which was successful. While the Infinity put up a fierce fight to regain control of the key, they were not able to retrieve it, and Jul 'Mdama left with both halves.
RELATED MEDIA
These events are depicted in the comic Halo: Escalation Volume 3, which was the subject of a Halo Book Club on September 6th, 2016.