Season 4, Episode 2:
On the Grid, a power struggle between Harry and Juliet emerges with Juliet blackmailing Harry into supporting her bid for the Security & Intelligence Coordinator's job. Harry refuses to be manipulated and offers his resignation. Adam manages to free Zaf and forces the kidnappers to reveal where the next bomb is -- it's under a high-rise block of flats. They defuse it but realize their policy must change; they have to root out the mole to find the bomb maker. Harry and Adam arrest their main suspect -- Juliet. As they subject her to an interrogation the Professor spots a Shining Dawn member in Thames House. The mole is the CIA man, Boyd. Boyd flees, using the waitress as a foil but is captured. The CIA offer Boyd a deal: reveal the bomb maker and you can resign. Boyd agrees and MI5 arrest the bomb maker, moments later the CIA assassinate Boyd. However, one final bomb is still ticking beneath a hospital and this time, the waitress is rigged to it. Move her and the bomb explodes. Adam stays by her side as they clear the hospital and the bomb ticks relentlessly downwards.