Unknown Signal is the last story mission in Tom Clancy's The Division.
After receiving a message from Faye Lau congratulating the Player about how they were able to take down not only the Last Man Battalion, but also the Rikers and the Cleaners, along with establishing some law and order on the streets of Manhattan, ISAC will receive a signal which will identify it as Shade Tech. Once this happens, the Player's GPS will automatically be mapped to its location, which is a ECHO beacon located in a small apartment block in the Chelsea district (if the Player has the Canine Unit unlocked already, the ECHO will already be revealed but will not be accessible until this point in time), at least 50 meters away from Camp Hudson.
Once arriving, the Player will enter said apartment block and make their way into a nearly empty room with only a small Hazmat tent with lab gear set up, a whiteboard, work bench and a small fridge with the entire room having tarps taped to them and the windows boarded up. Also located in the room is a body in Hazmat gear. Once the player activates the ECHO, it will reveal that it's not a past event in the crisis but rather a message left by rogue Division agent Aaron Keener with the body on the floor revealed to be suspected Bioterrorist Gordon Amherst himself now deceased, apparently by coming into contact with the Green Poison - his own creation.
At first it shows Aaron sitting in the Hazmat tent, but then shows him moving towards the whiteboard with notes attached to it (with the ECHO showing a few are missing), then to Gordon's laptop and notebooks (again, a few items are missing), then to the fridge where, according to the ECHO, had a 3D DNA biological printer and some viral samples being taken by Aaron and placed into a duffel bag. During these scenes, Aaron is addressing the Player about what had happened in the Dark Zone, and the Joint Task Force's decision to pull out, which lead to Aaron turning on the Division and how he had planned to invite the Player into joining his plans and his small unit of rogue agents, but then taunts the Player about how they have sworn an oath of loyalty to the government and that he believed that the Player would have engaged him. He then states that he intends to continue on Amherst's work by making a new, and possibly, more deadly virus due to him having Amherst's gear, samples and notes and Vitaly Tchernenko to help him (potentially by force) achieve this. Throughout the message, if the Player looks at Aaron, the info attached to him will show what it has been with all other ECHOs that he appears in (Status: AWOL, Occupation: Division Agent, File Compromised), but then it will change to reveal that he is now a disavowed agent and was working alongside Colonel Charles Bliss and the LMB.
The Last ECHO 'pop-up' that appears shows Aaron about to leave through the door the Player came in, with the duffel bag and also leaves a final message inviting the Player to enter the Dark Zone and see what he saw himself before saying his farewell to the Player. By this time, the Info attach to Aaron reveals that he is now wanted for high treason, indicating that the government is now fully aware of Aaron's activities and intentions.
Upon seeing all of the ECHO, the Player will be rewarded with Virus Progress Report 5, which is Amherst's own views on the Green Poison.
- Seeing as how the room is set up, it is highly believed that the Green Poison virus was created and manufactured in the same location as the ECHO.
- Once the Player access the ECHO for the first time, they will be able to access it at any time. However, should the player either join a different player's session or log out, then this room will be barricaded off hereafter and will not be accessible unless the Player creates a new agent. However, should the player join a different session and they haven't accessed the ECHO, then you can return to see the message.