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!
Adam infiltrates a truck carrying illegal immigrants across Europe in order to stop a would-be terrorist.
The episode was rated 7.60 from 101 votes.
MI5 suspect a terrorist is planning an attack from his prison cell. Guest stars Jimi Mistry.
The episode was rated 7.70 from 93 votes.
An old British traitor is called on to infiltrate a Russian firm suspected of stealing secrets from GCHQ.
The episode was rated 7.71 from 99 votes.
Far-right political party The British Way is threatening democracy so Adam and Fiona go undercover to infiltrate and destroy its campaign.
The episode was rated 7.72 from 90 votes.
Harry upsets the CIA by stopping an extradition to the USA.
The episode was rated 7.76 from 92 votes.
When a devastating bomb explodes in central London, causing multiple deaths, a terrorist group with a hatred for human life claim responsibility. With their leader facing extradition, the bombers announce that crippling attacks will be launched at ten hour intervals until he is released.
The episode was rated 7.81 from 120 votes.
Zafar and Adam race against the clock to uncover the latest bomb. As a new ultimatum is issued and Tash mysteriously disapears, the team is forced to deal with the possibility of a mole within their own organisation.
The episode was rated 7.90 from 111 votes.
The Syrian foreign minister tries to establish subversive contacts with MI5 at the opening of a cultural centre in London. Fiona is desperate to lead this mission and must confront her Syrian past.
The episode was rated 7.96 from 95 votes.
A former officer is convinced that MI5 killed Princess Diana and is determined to force the team to prove it.
The episode was rated 8.04 from 94 votes.
A neo-conservative group murder an ex-minister to cover up his past and then they hunt down the journalist who is threatening to blow the story and is under MI5 protection.
The episode was rated 8.06 from 96 votes.
