Slow Horses season 4 ending explained: Who was Frank?

Meanwhile, a suicide bomber at the start of the season kicked off a chain of events leading back to Frank Harkness, a mercenary who had fathered children by different women, taken them from their mothers and raised them to be his loyal followers.

But just who was Frank really, what happened to him, and did the Slough House team make it out alive?

Read on for everything you need to know about the ending of Slow Horses season 4.

*Warning - contains full spoilers for all six episodes of Slow Horses season 4*

Slow Horses season 4 ending explained: Who was Frank?

After being ambushed in the previous episode, River is brought to meet Frank Harkness at a bar. As some fans may have guessed by now, River greeted him by revealing exactly who he was, saying: "Hello, dad."

That's right, Frank was River's father, and River himself had realised this based on birthday cards he had been sent as a child.

His mother had told him that his father had abandoned him, and then died in a car crash. David had kept the truth from River all of his life.

While Frank wasn't exactly touchy-feely in their first encounter, admitting that he had never loved River's mother, he went on to offer River a job.

River wasn't interested, admitting he was glad he hadn't been raised by Frank and revealing that Yves's bomb wasn't intended as a declaration of war on the west, but instead of war on Frank himself, bringing him into the light.

What happened to Frank?

While at the bar with Frank, River called Louisa, and she got Roddy to trace the call. Louisa brought in Emma and a group of police officers, who ended up in a stand-off with Frank, as he held a gun to River's head.

An incoming group of additional MI5 agents, with a shoot to kill notice on River from Claude, complicated things. Frank escaped, using a grenade to create a panic.

Following a chase, River found Frank hiding in plain sight at St Pancras station. Impressed with River's work, he handed over his gun and gave himself up to Emma and Louisa. River then revealed to Louisa who Frank really was.

After he was arrested, Diana interrogated him. Frank revealed to Diana that he had left a failsafe, and told her she would have to let him go.

Jackson later showed Diana a selection of letters written to the heads of the intelligence services. They said that she had 12 hours to let Frank go, or the letters would go up on the internet, and expose the fact that MI5 had repeatedly used Frank's services over the years to do its "dirty work".

The implication was that Frank would soon be let go - meaning he's still out there somewhere...

Did the Slough House team make it out alive?

Sadly, no. The rest of the Slough House team found themselves in a tight spot, after Moira called Sam to let him know where David was - unaware that one of Frank's team, his son Patrice, had Sam's phone.

As he attacked, the team tried to defend themselves. Roddy got shot in the arm, and Marcus went out to face him alone, and got gunned down in the process.

Just as Patrice was about to also kill Shirley, Jackson arrived and knocked him round the head from behind, before Shirley got some extra hits in to make sure he was subdued.

They handcuffed Patrice to a radiator, and when Jackson left to call the park, Shirley attempted to shoot him in the head. JK convinced her it wouldn't help things, and that Marcus wouldn't want her to do it.

She gave in, handing JK the gun, at which point he shockingly shot the assailant three times, killing him, breathing out a sigh after doing so. He then put his headphones in and walked off.

Where did we leave Jackson, River and the rest of the team?

Jackson arranged for Marcus's family to receive his salary going forward, providing for them for years to come.

Meanwhile, Moira accosted Claude, and revealed that she knew he was Galahad, and had been curb crawling. She managed to get her old job back from him, along with a four-day week and a pay rise.

Right at the end of the season, River arranged for David to live in a retirement home run by the Park. David berated River for making him move, but River insisted that he had to for David's own safety, and that he would visit every other day.

After leaving the home, River went to meet Jackson at a pub, where he made him sign an account of his movements. The pair sat together in silence and had a drink.

Slow Horses season 4 is available to stream in full on Apple TV+ now – sign up to Apple TV+ now.

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