Around fourteen years after Emergence Day, the Locust Horde organized a massive offensive to take Tollen Dam, the center of the COG's electric infrastructure in the dwindling COG territory. The Coalition would reinforce the dam from several nearby COG outposts, including Fort Reval. The Locust Horde was able to besiege the dam, trapping untold numbers of Gears inside. This led to a gradual loss in supplies and food, eventually causing starvation. Despite sending the famed Delta-One, led by Marcus Fenix, COG High Command was unable to break the siege. The Dam was overrun and taken offline by the Horde, causing the COG to abandon several cities and outpost due to the power loss. The COG would later downplay the losses suffered during the battle, saying only a few dozen Gears were trapped inside.
- Gears of War 4 (First mentioned)