The Diplomat Season 3 Ending EXPLAINED: Political Thriller Has One More Twist About US-UK Relations In Finale

Created by Debora Cahn, The Diplomat is focused on a political couple, Kate (Keri Russell) and Hal Wyler (Rufus Sewell), whose marriage has been on the rocks. This season, their marriage hits an even bigger

speed bump after one of them becomes the vice president of the United States. The couple must put their differences aside to come together for the greater good of the country as they negotiate a dangerous situation between the US, UK, Russia, and China. Here's what happened. Warning: Spoilers ahead!

Which Wyler is vice president of the US?

After Grace Penn (Allison Janney) becomes president after the death of William Rayburn by heart attack, the former vice president needs her own second in command. Her dislike of Kate continues as she doesn't select her but her husband, Hal, as her VP pick. It leads to the first big crack in the already tense relationship between the Wylers. Hal doesn't want to accept unless Kate is on board, and she can't come in the way of this big opportunity. However, she is loath to give up her post as US ambassador to the UK, something she worked very hard to achieve. Instead, she will remain back in England, while Hal will continue as vice president in Washington, DC.

Who does Kate move on with?

When Hal returns to London to surprise Kate at an event, he immediately clocks that she is having an affair with Callum Ellis (Aidan Turner). It turns out that Callum is actually an MI6 agent who is providing her with intel on Russian nuclear developments in the area. This creates further friction in the Wyler marriage, and Kate accuses him of being jealous.

https://www.youtube.com/watch?v=l6UX4V71jzc

Real suspects behind the bombing of HMS Courageous to be revealed Since Season 2, viewers are aware that it was actually Penn who initiated the bombing of the HMS Courageous, killing 41 British sailors. She is the one who pushed Prime Minister Nigel Trowbridge's (Rory Kinnear) confidante Margaret Roylin (Celia Imrie) to this decision. However, in Season 3, Roylin dies by suicide on the US's watch, and Trowbridge grows more distrustful of the Americans. CIA station chief Eidra Park (Ali Ahn) has a walk-in at the embassy who states that an American was involved in the bombing. The Russian official indicates that the information is going to be shared with the press very soon.ALSO READ:The Diplomat Season 3 Review: Keri Russell Returns With Poise In Sharper, Darker, Emotionally Charged Political Thriller

How does the US break the news to the UK?

Penn, Kate, Hal, and White House Chief of Staff Billie Appiah (Nana Mensah) go back and forth through various scenarios on how to tell the Brits. Penn is about to admit it was her when Kate comes up with a last-minute Hail Mary, which she has to relay to Penn’s husband, Todd Penn (Bradley Whitford). They will lay the blame on Rayburn, who is already dead, to mitigate the fallout.

Trowbridge and his advisor and Foreign Secretary Austin Dennison (David Gyasi) also fly in to meet the group at the President's home in Amagansett on Long Island. While Trowbridge is supposed to admit that it was Roylin who had masterminded the attack, he goes rogue and names Rayburn. It causes a big media frenzy that follows all of the US staff in England, unable to move about freely without the threat of attack.

What is Poseidon?

Besides this rift in the US-UK relations, another problem arises. Callum informs Kate that a Russian submarine is stranded close to the shores of the UK with a Poseidon missile aboard. The Russian nuclear weapon is capable of “doomsday”-level destruction. The duo have their first fight even as they decide that the only way both countries can handle the nuclear disaster together is if Penn apologises to Trowbridge. ALSO READ: The Diplomat's Allison Janney Reveals She Had No Idea About Role After Signing On, Drops Hints For Season 3While Penn doesn't agree to apologise, she offers the US's assistance in getting the missile out from the submarine. The meeting at Trowbridge's home doesn't go well, as he doesn't believe Penn. The Americans work around Trowbridge as they go take pictures of the Russian sub with their own vessel to convince Trowbridge of the danger.

What happens to Poseidon?

When presented with the evidence of the missile in front of him, Trowbridge still refuses the US's help. However, Hal whispers "Runnit Dome” to Kate. She goes and suggests to the UK PM that the Brits bury the Russian sub with the missile so that nobody gets access to it. Trowbridge reluctantly agrees. It seems everything is going to be normal again. A tearful Kate even asks to take her back again, seemingly ending things with Callum.

In the final five minutes of the show, Callum tells Kate that he thinks the Russians somehow came for the missile, as it is no longer there. Kate goes to warn Hal, and he rushes to tell Penn. That's when Todd Penn plants a seed of doubt in her mind, indicating that something is off between Hal and Grace Penn. It finally dawns on Kate it wasn't the Russians who stole the missile; it was the Americans. A furious Kate confronts Hal and tells him that he has used her to basically start a war with the Brits. Hal tries to shush Kate, and while they gather to take photos for the meeting, he tells Grace, "She knows."