Line Installation 1-4
From Halopedia, the Halo wiki
Line Installation 1-4 (simply referred to as "The Line") was a Forerunner installation located on an unknown Moon [1]. During the Human-Covenant War in the mid-2500's, 686 Ebullient Prism, the Monitor of the Line, took Human and Covenant personnel hostages after their crash-landing on the moon[2].
