Slow Horses season 3 ending explained: Did River and Louisa escape?

In the episodes leading up to the finale, we learned that Catherine Standish had been kidnapped by a tiger team, hired by private security firm Chieftain in order to demonstrate weaknesses in MI5's security, on the orders of Home Secretary Peter Judd.

However, Sean Donovan went rogue, as he had actually been set on the operation by Diana Tavener. She had learned about Judd's plans, and also knew that Donovan was looking for revenge for the death of his lover, Alison Dunn.

She planned for Donovan to get hold of files, locked away in a Park facility, which revealed the truth of Ingrid Tearney's involvement in a failed operation in Istanbul.

She had signed off on testing a device that could wirelessly hack encrypted computers. It hadn't worked, and the operation had left innocent people hospitalised and nearly got a senior North Korean spy killed. Alison had planned to reveal this publicly, so Ingrid had her killed.

Diana planned for Sean to find the files and leak them, leading to Ingrid's downfall. She saw ousting Ingrid as the only way she could ever get to the top and become director general of MI5.

The end of episode 5 saw River and Louisa locked in the facility with Sean and Alison's brother Ben, with Tearney's heavily armed MI5 operatives advancing, on orders to kill anyone inside. They killed Ben but, in the finale, did the others make it out alive?

Read on for everything you need to know about the ending of Slow Horses season 3.

Did River and Louisa escape the facility?

They did. With the help of Shirley and Marcus who keep many of the operatives trying to take them out busy, River and Louisa managed to make it right through the facility to an exit point.

There, they met Shirley, who let them out just in time through a hatch.

What happened to Sean and the files?

Unlike River and Louisa, Sean Donovan never made it out of the facility alive, being killed by the MI5 agents tasked with taking him and the others out.

However, his work wasn't for nothing. River got the files out of the facility and took them to his grandfather David. David told River that, to protect the reputation of the security services, the files had to be destroyed. He threw them into the fire.

However, River deceived his grandfather – he kept copies of the files in his car, which he subsequently leaked, believing Ingrid Tearney had to pay for having Alison Dunn killed.

What happened to Jackson and Catherine?

Jackson and Roddy managed to rescue Catherine from the safe house in which she was being kept, and stopped it from being raided by MI5. However, as they were travelling back and had stopped at a petrol station, things turned sour.

The pair argued when Catherine notes that he is being 'off' with her, and says that Charles Partner, the former director general of MI5, could always see through him.

This led to an argument about Charles, in which Jackson revealed the truth – that Charles was a traitor who spent 10 years selling secrets to the Russians. He said Charles kept Catherine on as his secretary because she was a drunk who wasn't alert enough to pick up on what he was doing, and that he laid a trail to pin all his dealings on Catherine.

Jackson suggested Catherine knew this all along but didn't have to coverage to admit it to herself. In the heat of the moment, she quit Slough House there and then, walking back from the petrol station rather than share a car with Jackson.

What Jackson didn't reveal to Catherine is that he killed Charles on David Cartwright's orders – as was revealed at the end of season 1.

Where is everyone else left ahead of season 4?

Shirley and Marcus were given their jobs back by Lamb, and the rest of the Slough House team, now minus Catherine, all went back to work.

Meanwhile, at the end of the season Diana Tavener had managed to win in her twisted game against Ingrid Tearney, as River and Louisa escaped and the former leaked the files.

This meant Ingrid had to leave her job in disgrace and Diana rose to the top rank in MI5, as the new director general.

Slow Horses seasons 1-3 are available to stream now on Apple TV+ – sign up to Apple TV+ now. Check out more of our Sci-Fi coverage or visit our TV Guide and Streaming Guide to find out what's on.

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