Operation: JOVIAN WHISTLE was an operation executed by the UNSC 717th Xeno-Materials Exploitation Battalion to recover a Forerunner ancilla on the human colony world of Gao in the Cordoba system in the early summer 2553. Due to a recent event on a nearby Forerunner installation on the planet Shaps III, the ancilla Intrepid Eye was awakened and attempted to contact the Forerunner ecumene to determine its status and orders. With no contact made with Forerunners, and human colonists on Gao found nearby, the AI began killing people who got close to its installation. At the same time that the UNSC sent the 717th to investigate and capture the ancilla, the Keepers of the One Freedom, a Jiralhanae-led religious group, also made planet-fall and attempted to capture the ancilla for themselves. A battle ensued on Gao over the ancilla, with the UNSC eventually managing to leave the colony with Intrepid Eye.