Brian Gideon, a disgruntled chemical engineer, learns that S.T.A.R. Labs is producing weapons of mass destruction based on his research for the United States government and uses an cloaking device to infiltrate S.T.A.R. Labs and retrieve the weapons, but his plans go awry, and Tina and her employer Ruth Wenerke are exposed to a deadly neurotoxin. While attempting to locate both Gideon and a cure, Barry clashes with federal agent Jack Quinn, who is trying to cover up Gideon's involvement in the crisis. Barry confronts Gideon, who injects him with the toxin in order to escape, but Barry is able to burn it off his body, and use his blood to inoculate Tina and Ruth. Gideon is then arrested, while Ruth cuts ties with Quinn, who is detained when the activities he illegally sanctioned for Gideon are exposed.