Isaac Barnes is a no-nonsense representative of the United States Government. He wears Glasses. When the threat of a possible Soviet invasion of the island nation of Khios, Barnes and General Morgan Hawkins were sent to UNITY Headquarters to request assistance.
Barnes was able to provide information that Project: Omega was a secret Soviet weapons program that was being coordinated out of a remote base in Siberia. Bruno Lawrie agreed to send UNITY undercover agent Cate Archer to see what she can find out from the facility.
When Archer returns from Siberia with information that Project: Omega was the brainchild of H.A.R.M., Barnes states he was looking for something a little more conclusive. Archer believes that she can find more information within the house of Melvin Blitzny in Akron, Ohio.
When General Hawkins shows his plans to invade the Soviet Union, Barnes commented that the plan was not very detailed. When the Mimes invaded UNITY Headquarters, Barnes took cover from the assault. In the second Mime attack, the UNITY Intercept Team had to rescue Barnes who had been cornered.
- The second mime attack took place in the cooperative mission "Mime to Kill"
Archer found a memo from Barnes containing a situation report. In it he casts doubt that the Soviets wanted to put up a Communist super casino and believes that their true aim is to exploit the island's natural resources. He noted how the Soviet involvement would interfere with the planned manipulative exploitation by NATO.
Barnes was present with the NATO blockade around Khios when Project: Omega was launched by H.A.R.M. When Magnus Armstrong was able to restore the Khios flag, Barnes proclaimed that they had to destroy the Missile launched by General Hawkins. After the missile was destroyed by a laser, Barnes gives a sigh of relief.
Hawkins "As you can see from this diagram, I've got it all figured out. You give me twelve hours, I'll give you Mother Russia."
Barnes' "Not a very detailed plan of attack."
Hawkins "We can work out the details later. The first thing is to get El Presidente to sign off on the idea."
Barnes' "Let me know what he says."
"General Hawkins was just explaining his plan for invading Russia. Of course, he left out the part where he describes what actually happens during the invasion. Too bad his zeal isn't matched by his intelligence."
- A production drawing of Isaac Barnes can be seen in the final credits of the game.