 Repeated attacks on MI5 s computer system threaten the theft of virtually all classified information. Danny is undercover as a journalist for an socialist paper linked to an anarchist group while Zoe takes a turn as a middle school teacher to get close to another instructor who may be spearheading the computer attacks. Moreso than other episodes, though, everything is not as it seems as a long-dead agent and a potential nuclear device at the school play into a web of deceit and confusion that nearly costs MI5 all their secrets.