The Diplomat ending explained: Who ordered the attack?

Kate Wyler (Keri Russell) in her red evening dress in The Diplomat season finale
(Image credit: Alex Bailey/Netflix)

The Diplomat is the latest political thriller to take off on Netflix, and plenty of people have already raced through the eight-episode series from The West Wing's Deborah Cahn.

If you've gotten wrapped up in all the drama but still need The Diplomat ending explained, we've laid out what happened in the season finale of Netflix's latest hit. The final episode was packed full of some truly shocking revelations about the international incident at the heart of the show and saw US ambassador Kate Wyler (Keri Russell) uncovering a big secret at the heart of British politics.

Be warned: there are some big The Diplomat spoilers ahead, so don't read on if you aren't caught up just yet. And if you need a refresher on some of the key characters in the show, have a quick read through our The Diplomat cast guide.

The Diplomat ending explained: Who ordered the attack on HMS Courageous?

After uncovering that neither Iran nor Russia was actually behind the attack on the British warship in the series pilot episode, Kate and her government allies were trying to find out who'd hired Russian mercenary Roman Lenkov to attack HMS Courageous.

In the penultimate episode, a Russian ambassador secretly handed over Lenkov's whereabouts to Kate in a meeting; he would be in Paris in ten days' time. Prime Minister Nicol Trowbridge previously wanted to go after Lenkov's men in Libya, though he was subsequently told to stand down by the US Secretary of State, Ganon, and try to arrest Lenkov...something he made abundantly clear that he was not very happy about to Kate in an explosive rant.

In the season finale, Foreign Secretary Austin Dennison revealed that Trowbridge had changed his mind overnight and wished to go ahead with the arrest after all. He and Ganon would be travelling to Paris, though Stuart Heyford told Kate Ganon also wanted her to go over there. Kate leaves Hal in London, and he takes her place at an event to give a speech at Chatham House.

Kate Wyler (Keri Russell) on the phone in The Diplomat season finale

Kate learns about Hal's meeting on the phone. (Image credit: Alex Bailey/Netflix)

After Hal delivers his speech, he's approached by Merritt Grove, a Tory MP. Grove wanted to speak to Kate, but as she was unavailable, Hal offered to speak to Grove himself. Hal calls Kate to pass on the news. She accuses Hal of going way over the line and believes he's gunning for the Secretary of State job, orders him not to meet Grove under any circumstances, and says her office will speak to the MP instead.

Following her call, Kate takes a call from Maggie Roylin, a political advisor to Trowbridge. On the phone, she asks about Grove and tells Maggie that he wanted to meet with Hal, before telling Austin Dennison about the state of her marriage to Hal. 

Whilst all this is going on, Stuart Heyford tries to convince Hal to back down, but he flat-out refuses. that evening, Kate attends an event at the Louvre in Paris to try and get the support of French Minister of the Interior, Fournier, in the arrest of Roman Lenkov.

There, Fournier reveals that London had asked to take the lead on the operation and drops the bombshell that UK special forces were planning to assassinate Lenkov, rather than arrest him. Kate and Dennison soon realize that the only person who would want Lenkov dead is the person who hired him in the first place, to stop him from revealing such info... meaning Trowbridge must have been behind the attack after all.

Back in London, Hal, Stuart and his assistant Ronnie go to meet Merritt Grove. Ronnie finds him first, but Grove refuses to speak to anyone from the US embassy except Hal and leaves the restaurant. 

Ronnie pursues Grove to his car, and Stuart and Hal begin walking toward him from different ends of the street. As Grove reaches for the car door, the vehicle explodes, leaving Hal, Grove, Heyford, and Ronnie's fates up in the air. Back in Paris, Kate and Dennison are surrounded by security, who presumably inform them of the attack. Talk about a cliffhanger ending!

We're left with a ton of questions that we hope will be answered in The Diplomat season 2. Who ordered the attack on Merritt Grove? Did anyone survive the bombing? And will Kate and Dennison manage to bring Trowbridge's actions to light anytime soon?

The Diplomat season one is available to watch on Netflix right now. For more shows to enjoy, check out our guide to the best Netflix shows you should be streaming in 2023.

Martin Shore
Staff Writer at WhatToWatch.com

Martin is a Staff Writer with WhatToWatch.com, where he produces a variety of articles focused on the latest and greatest films and TV shows. 

Some of his favorite shows are What We Do In The Shadows, Bridgerton, Gangs of London, The Witcher, Doctor Who, and Ghosts. When he’s not watching TV or at the movies, Martin’s probably still in front of a screen playing the latest video games, reading, or watching the NFL.