The Missing Link

The Missing Link is the first add-on for Deus Ex: Human Revolution, developed by Eidos Montreal in co-production with Square Enix and was announced to be released simultaneously for PC, PS3 and Xbox 360 in October 2011. The Missing Link was released on October 18th on PS3, Xbox 360 and PC in North America. In Europe, it was released on October 18th for Xbox 360 and PC, and October 19th for PS3.

Plot
The Missing Link explains what happened to Adam Jensen during his three day disappearance after he left Hengsha a second time. Waking up tied to an electromagnetic chair that inhibits augmentations, Jensen bears the torture of the ship's augmented second in command, Netanya Keitner, who believes he is a spy with government or company affiliations. After the torture equipment strangely deactivates in Keitner's absence, Jensen flees the area in an attempt to escape.

Sneaking his way through the ship, Jensen is briefly contacted by a mysterious man over his radio, who then gives him directions to his equipment. Mysterious man speaks with russian accent, using 'bratan' - russian for 'bro', while adressing Jensen. After regaining his vest and passing through several areas, Jensen then escapes the ship when it docks at an oil rig owned by Belltower, and is told by his mysterious contact to rendezvous with a mole. Upon reaching the rendezvous, it is revealed that Keitner is a double agent working for Interpol, who are attempting to gather evidence on Belltower. Keitner then tells Jensen that she was the one that released him, and that he will need to help her gather enough evidence to incriminate Belltower.

Making his way through the detention blocks filled with kidnapped innocents being held prisoner, Jensen eventually overhears Pieter Burke, the augmented commander of the base, telling scientists Savage and Kavanagh to continue research in a hidden lab. After stealing one of Burke's spare prosthetic eyes, Jensen uses it to gain access to the lab with the help of Keitner's friend Garvin Quinn. Decending into the underwater lab, Jensen confronts Dr. Kavanagh, who agrees to testify against Belltower in exchange for protection.

After heading back up to the base, Keitner discovers that Burke has discovered their plan, and is fatally wounded in a firefight with several soldiers and dies shortly after Jensen reaches her. Burke then begins to flood the underwater base and the prison cells with toxic gas to remove any potential witnesses; with the option of diverting all the gas to one of the two areas, Jensen is then forced to either save hundreds of lives or the only person who can testify against Belltower. A third, hidden option is present; by accessing a vent in the nearby area, Jensen can destroy the gas dispenser, saving both parties.

After saving one or both of the targets, Jensen then makes his way to Burke, and is given the choice of killing or sparing him; regardless, the mysterious man contacts him again and tells him another ship has been found that will take Jensen directly to Megan Reed's location. Upon reaching the dock, it is revealed that Jensen's mysterious contact is actually Quinn, who explains that he hired Keitner under the guise of an Interpol agent, and that he was withholding the truth from both Jensen and Keitner to use them as pawns against Belltower and in extension the Illuminati. Quinn then proceeds to either commend or question Jensen's actions (based on whether he saved or sacrificed Kavanagh), before placing him back in a cyrosleep pod.

After Jensen reenters cryosleep, he is airlifted to the ship by helicopter as Quinn discusses Jensen's potential use as an ally with his superior, Janus, only to be dismissed due to Jensen's obsession with Megan.

Characters

 * Netanya Keitner
 * Pieter Burke
 * Garvin Quinn
 * Tiffany Kavanagh
 * Gary Savage (cameo)

New features

 * At the beginning of The Missing Link, Adam is stripped of his use of his mechanical augmentations, allowing the player to remake their character as they wish with the same total level of praxis kit they had before
 * The new environments in the add-on feature improved lighting effects as well as upgraded weather effects such as rain.
 * Add some new elements to the main plot
 * New characters linked to the main plot
 * New environments
 * New shirtless "outfit" for Adam Jensen during the add-on
 * 10 new achievements/trophies for the console versions
 * A new golden revolver skin (equipped by Burke)

Easter Eggs

 * The topmost left stasis pod in the storage area has a woman, named RZZRGRRL, with specular eye implants and titanium implants under her fingertips. This is clearly an homage to "Molly", the Razor Girl, one of the main characters of Neuromancer, the Cyberpunk Manifesto by William Gibson.
 * In another pod, players can read about the descendant of some people stranded on an abandoned island, coordinates around 10°S 110°E, referencing LOST.

Developer quotes
"Gamers will be able to experience a vulnerable side of Adam like never before, which gives the overall game a whole new dimension. 'The Missing Link' propels players into compelling gameplay, beginning with Adam being temporarily stripped of his use of augmentations; new, visually stunning environments; and the continuation of Deus Ex: Human Revolution’s conspiracy-rich story."

- David Anfossi