Section One uncovers a possible Red Cell munitions outpost in Glasgow, Scotland, and sends a team of operatives to overtake and neutralize the facility. Instead, Mowen, the operative who enters the Red Cell installation, returns to Section One bringing a deadly virus back with him. One by one, operatives become infected and die. Nikita and Michael feverishly work to find Dr. Bisseroff, the only man who might have an antidote. Meanwhile, Gail ceases her relationship with Birkoff because she's dating another operative, Janklow.