Admiral Kahoku has asked you to investigate the wherabouts of a missing Marine recon team. Their last known location was the Sparta System in the Artemis Tau cluster. Kahoku is found in the Citadel Tower near the steps leading up to the Council meetings.
You can find them on Edolus, while you are investigating the source of a distress call. You will discover that they were killed in an ambush near a Thresher Maw nest and you will be forced to fend off said monster.
Return to the Citadel Tower and speak to Kahoku to complete the assignment. Later, Kahoku will contact you with information on the ambush and give you the UNC: Cerberus assignment.