Tense drama series about the different challenges faced by the British Security Service as they work against the clock to safeguard the nation. The title is a popular colloquialism for spies, and the series follows the work of a group of MI5 officers based at the service's Thames House headquarters, in a highly secure suite of offices known as The Grid.
Written by Sophie and last updated on nov 28, 2022.
PS: The following content contains spoilers!
PPS: I will admit that parts of this page was written with the help of AI - it makes my work so much easier to not start from a blank page!
With Lucas back within MI5 he reveals that the Russians interrogated him about Operation Sugar Horse, the most secret ongoing spy operation MI5 ever had. If the Russians know about it, then MI5 has a very high level mole. Harry seeks out his mentor, The Spycatcher, to help him find the mole. Ben is undercover with an Al Qaeda cell; they are planning to bomb London and what looks like a dry run unexpectedly turns live.
The episode was rated 7.70 from 80 votes.
The team are stunned to discover that Al Qaeda's number three wants to negotiate. It's a risk, but Harry and the team have to take this chance for peace.
The episode was rated 7.99 from 80 votes.
The British economy is on the brink of collapse and if one more bank goes down the entire financial system will implode. Ros goes undercover in the City to flush out a dangerous international financier who wants to bankrupt the country. Suddenly, it is not just the economy, but Ros's life that is at risk.
The episode was rated 8.05 from 76 votes.
A teenage boy accidentally stumbles upon a government conspiracy and is instantly absorbed into the world of MI5, ending up on the run. Lucas and the team battle to protect the boy from those who wish to silence him. Harry receives a cryptic message from his asset in Russia which could be the key to bringing down the high-level MI5 mole.
The episode was rated 8.13 from 75 votes.
Harry vows revenge by taking down the Head of Russia's intelligence service in Britain with the help of Lucas North. Lucas's loyalties, however, are secretly no longer with MI5 and he exploits Harry's trust to help a Russian submarine destroy Britain's communications system, causing financial and social chaos.
The episode was rated 8.14 from 72 votes.
The team step in when a British soldier is kidnapped by al-Qaeda. Meanwhile, an old protégé of Harry's returns to the fold after eight years in a Russian prison - but whose side is he really on?
The episode was rated 8.25 from 73 votes.
Harry is imprisoned and accused by MI5 of being the Russian mole. Lucas disappears to Moscow in a bid to gather intelligence and get to the bottom of Harry's arrest, whilst the rest of the team try to prove his innocence on the Grid. But with so much evidence against him and a traitor among the team, things aren't looking good for Harry.
The episode was rated 8.44 from 66 votes.
With the Russians launching a nuclear strike on London, the only person who can help the team in this desperate hour is the traitor amongst them. With the Russians hunting them down, the team usher their traitor through London in a desperate bid to reach the codes, and the bomb, in time.
The episode was rated 8.54 from 72 votes.
