The Diplomat season 2 episode 4 ending explained: Who attacked the HMS Courageous and Merritt Grove?

Spoilers ahead of The Diplomat season 2 episode 4

The events of The Diplomat season 2 have been building toward episode 4, "The Other Army," and the reveals in this episode were explosive. So much so that by the end, someone's life is hanging by a thread. It all starts when Margaret Roylin still won't give up what she knows about the attack on the HMS Courageous and the car bomb that killed MP Merritt Grove and Ronnie Buckhurst.

She insisted that Prime Minister Nicol Trowbridge wasn't a part of anything that happened, but she wouldn't disclose to Ambassador Kate Wyler because Roylin believes she'd be compelled to act and would focus on what didn't matter. Seeing that they weren't getting anywhere, Kate suggested that Roylin tell Hal Wyler. Kate and her husband have a "magic trick" that allows them to carry out their duties and gain information by having one of them be the vault that receives information and only doling out the pertinent bits to the other. She served in this function for him, now it's Hal's turn.

Roylin agreed and what she told Hal shook him when they met privately with the CIA out of earshot. He told Eidra Park, the chief of the CIA's London station, that they couldn't hand Roylin over to the cops and Foreign Secretary Austin Dennison couldn't resign in order to expose Trowbridge. The latter part is also because Roylin wasn't lying. The PM didn't know what happened. She told Kate and Eidra, with Hal present, what really went down the day the aircraft carrier was attacked.

Who really attacked the British warship on The Diplomat?

The stunning secret that Roylin was holding onto was that she was a part of the attack. She along with Grove, an MP named Lenny Stendig, and more co-conspirators that she wouldn't name, wanted a unifying event. Roylin's the one who hired Lenkov but he was supposed to use limpet mines. They're magnetic. They would have stuck to the ship's hull and been strategically placed so they'd cause the least amount of damage. The intent was to create two meters of bent metal and generate a great deal of outrage but limpet mines weren't available so Lenkov had to use a small anti-ship missile.

While this wasn't in the plan, it was deemed acceptable because the missile would cause a large hole but not much else. No one was supposed to get hurt. But what they weren't aware of at the time was that the HMS Courageous had a damaged propeller shaft. To access it, the crew of the ship had to empty the fuel storage area in the back of the carrier and place the spare tanks in a hangar under the deck located in the middle of the ship. That's the exact spot the missile hit and the hangar contained 120 tons of diesel fuel.

41 British officers died and it was their fault. Grove was struggling to carry the weight of it which is likely why he reached out to Hal. Roylin told Stendig to do something about his fellow MP, but she meant he should speak to him. That's not what Stendig did.

Who killed Merritt Grove and Ronnie Buckhurst?

Stendig is the one who put the bomb in Grove's car. He's a member of the far right in government and he's always been difficult for them to control. It seems he's now graduated from accidental murder in the name of keeping his country together to a planned homicide with collateral casualties to do the same.

The unifying event they wanted did happen, and he wasn't going to let Grove upend it. If the truth were to out, it could end the UK has the people and the world know it. After all, an attack was launched on British citizens by British citizens in order to trick the kingdom into staying resolved as a nation with Scotland remaining in the fold, the UK's allies supporting them, and democracy intact.

Having heard this all, Kate decided that Roylin needed to tell Trowbridge so they could learn whether he truly is as innocent as his favorite advisor says. Eidra agreed to tap his phone to get this answer, but she did so with reluctance. It turns out that should have been the least of her concerns considering the PM's reaction.

Nicol Trowbridge killed Margaret Roylin...maybe

"The Other Army" ended in Scotland. Trowbridge, Kate, Hal, Eidra, and Stuart were there for his visit with First Minister Jemma Doud. Kate and Eidra organized a meeting with the PM and Roylin. Dennison was watching with Eidra and her agents, he'd been invited along by Kate and had to accept her invitation after Hal let him know he knew Dennison was planning to sleep with his wife the night he'd been caught in the blast of the car bomb.

Roylin had wanted the Foreign Secretary there so he could learn the truth. What no one expected was that Trowbridge would react violently to Roylin's confession about the HMS Courageous and her involvement in the attack. He strangled her and started railing about her being responsible for killing 41 people. Everyone launched into action, Dennison got a hold of Trowbridge but Roylin's chair had been leaning back on its legs.

When she fell, she hit her head hard. She was bleeding extensively and was unable to speak as Kate tried to assess if she was okay. It was a wild ending to episode 4 and the best set-up for what's set to happen next in episode 5!

Stay tuned to Americans Undercover for The Diplomat coverage. All six episodes of season 2 are available to stream on Netflix. Follow us on X for more content!