Brian Gideon, a disgruntled biophysicist, learns that STAR Labs is producing weapons of mass destruction based on his research for the United States government and uses a cloaking device to infiltrate STAR Labs and retrieve the weapons, exposing Tina and the project administrator Ruth to a deadly neurotoxin. While attempting to locate both Gideon and a cure, Barry clashes with federal agent Quinn, who is trying to cover up Gideon's--and Quinn's--involvement in the crisis.