Soldier! What is said here might be highly classified and could affect you, so be careful!
This article contains spoilers pertaining to the Resistance series. Read at your own risk!
Operation Black Eden was a last-ditch combat operation planned and executed by SRPA against the Chimera, during the Chimeran War. This was a final victory for SRPA and United States military forces during the invasion.
By mid-1953 the United States, if not the entire North American continent, was completely overrun by the Chimera, leaving a precious few millions of survivors scattered across the country and the remains of the U.S. government relocating to the last safe zone in Baton Rouge, Louisiana.
The course of the invasion led the Chimera, commanded by Daedalus, to relocate the Chimeran fleet to the Chicxulub Crater for their mysterious plan involving the power channeling of the Chimeran tower network across the globe into the fleet's flagship.
Dr. Fyodor Malikov, who was stationed in Cocodrie, Louisiana, observed the entire Chimeran fleet over the crater and came to the conclusion that detonating a nuclear bomb in the middle of the fleet would destroy everything within the crater. Malikov convinced Major Richard Blake to carry out this risky operation, eventually dubbed as Black Eden, as a last effort to stop the Chimera's plan and destroy Daedalus. Prior to this operation Blake procured SRPA's six kiloton fission bomb (codenamed "Nellie") and insisted to his superiors that Nathan Hale, who was close to succumbing to the Chimeran virus, be involved in the mission as Blake believed that including Hale was the best chance they had for the operation to succeed.
Blake brought Nellie to Cocodrie in order to have it on board the flagship by hijacking a Chimeran shuttle. However, while the bomb was being transported into the town, Blake's convoy was attacked by Chimeran forces. The bomb's delivery was temporarily thwarted, with Blake separated from the bomb when he was attacked by Stalkers while en route. Eventually, Corporal Joseph Capelli and Victor Company found the bomb and were forced to defend it. Nathan Hale also arrived and helped in defending the bomb as Capelli repaired a Chimeran Hornet to carry the bomb to a nearby Chimeran shuttle depot. After Capelli went to deliver the bomb, Hale went to search for Blake and eventually found him with X-Ray Squad.
Hale, Blake, and X-Ray regrouped with Capelli and Nellie, and arrived at the depot. After eliminating the depot's Chimeran forces, the group boarded a shuttle and traveled to the flagship undetected.
Once on the ship the group split up with Blake and X-Ray Squad delivering Nellie to the ship's reactor core while Hale and Capelli going to the ship's bridge in order to direct Blake and X-Ray Squad to the reactor. While on the way to the reactor, Blake and X-Ray were overwhelmed in a Chimeran ambush. Radio contact was lost, and it is later revealed that they had all been killed, with Nellie taken by Chimeran forces and brought to Daedalus to personally dispose of the bomb. Hale, with radio coordination from Capelli, tracked Nellie and confronted Daedalus.
After Hale killed Daedalus, he was overwhelmed by a powerful source of energy upon touching Daedalus and found himself possessing Daedalus' powers. Nellie was activated, Hale and Capelli escaped the flagship at the last minute as the nuclear bomb exploded, engulfing the flagship and annihilating the entire Chimeran fleet. The electromagnetic blast from the explosion disrupted Hale and Capelli's shuttle and forced them to crash land.
With the loss of Major Blake and X-Ray Squad, Hale and Capelli were the only individuals that survived the operation. Following the destruction of the Chimeran fleet, and despite what SRPA had done, the detonation of Nellie had caused to "kick-start" the tower network, creating a energy surge towards hud tower in New York City and creating a wormhole over the city, opening a portal to two planets/moons that presumably appears to be the Chimera's homeworld. This unexplained incident had been Daedalus's and the Chimera's actual plan, but the full details of which are still unrevealed. Furthermore, Hale was succumbed to the Chimeran virus and was forced to be killed by Joseph Capelli.
After Hale's body recovered, Dr. Malikov examined and studied Hale's corpse and found an unique antigen and protein in Hale's blood which become basic cure for the Chimera Virus. Joseph Capelli and all Sentinel survivors were inoculated by Hale Vaccine and no longer using Inhibitors.