The Diplomat season 2 recap: Everything to know before watching season 3

The Diplomat season 2 picks up minutes after the Notting Hill car bombing that closed season 1, immediately resetting the board. The Diplomat season 2 opens with British MP Merritt Grove confirmed dead while Hal, Stuart and embassy aide Ronnie are in surgery. By the end of the premiere, Ronnie succumbs to injuries, deepening Kate’s resolve and Stuart’s grief. Across six episodes, Ambassador Kate Wyler and Foreign Secretary Austin Dennison test an uneasy alliance as they pursue whether Prime Minister Nicol Trowbridge ordered a false-flag strike on HMS Courageous. CIA station chief Eidra Park runs parallel channels, and Hal freelances in ways that both help and endanger Kate.

A St. Paul’s Cathedral gambit drags fugitive fixer Margaret Roylin into public view, rattling Trowbridge and tipping the investigation. Then the floor gives way. Roylin ordered the attack, but the idea came from U.S. Vice President Grace Penn, tied to stopping Scottish independence and protecting the UK’s nuclear submarine base. Hal brings that intel to President Rayburn. He dies mid-call, and Grace becomes POTUS. That is where season 3 begins, with Keri Russell, Rufus Sewell, David Gyasi, Ali Ahn, Ato Essandoh and Rory Kinnear locked into the fallout.

The Diplomat season 2's immediate aftermath: The car bomb, St. Paul’s and how the case reopens

Episode 1, "A Stranger Calls," takes place in the ER and at Downing Street. Kate moves between triage updates and crisis rooms while Dennison confirms Grove as the casualty. Hal survives, Stuart is shattered and Ronnie’s death reorients the embassy’s priorities. The Diplomat season 2 uses that loss to harden Kate’s risk tolerance and to push Dennison closer, even as both know trust is provisional. Trowbridge keeps beating the war drum in public, echoing his earlier vow to “rain hellfire” on enemies.

Episode 2, St. Paul’s, turns a state funeral into a manhunt. Eidra ghosts Roylin into the cathedral, Trowbridge spots her from the lectern, and Hal engineers a clumsy cane drop to stall the Prime Minister just long enough for Roylin to slip the net. The escape proves Roylin is alive and still central. Back at the embassy, Stuart lashes out in grief and tells Kate her call to Roylin set a terrible chain reaction in motion. Kate and Dennison split on disclosure. She wants a path that protects the alliance. He wants the scandal contained without burning the institutions he serves.

Unmasking HMS Courageous: Roylin’s order, Grace Penn’s idea and the motive

Through the middle run, suspicion shifts from Trowbridge to the network around him. Roylin emerges as the contractor who hired Roman Lenkov, with enough cut-outs to grant the PM plausible deniability. When Dennison pushes too hard, Trowbridge loses his temper and physically corners Roylin, a moment that exposes both his volatility and his fear.

The Diplomat season 2 continues to weave the strategic stakes at Faslane into the dialogue, making clear why a manufactured incident that binds London and Washington would tempt actors who fear a post-union Britain. The break comes late. Kate learns that Grace Penn originated the HMS Courageous idea before it was operationalised by Roylin. Grace frames it as ruthless statecraft that preserved the special relationship and NATO posture. Kate counsels containment rather than catastrophe. Hal refuses to sit on the truth. The marriage turns into a policy fight. Kate tries to manage it inside the system. Hal decides to go over it.

The Diplomat season 2 finale, explained: The lawn sprint, succession shock and where every character lands

Episode 6, Dreadnought, stages the collapse at an American state dinner. Kate nudges Hal to tell Grace “we know,” and Grace steps out to confer as the Secret Service suddenly sprints toward her on the Winfield lawn. Off-screen, Hal has already bypassed State. On the phone with the Oval, he hears a thud, followed by silence. He calls Kate and says,

“He died, Katie...The president is dead. Grace Penn is president.”

The Diplomat season 2 ends with Grace absorbing the handover, while Kate realizes the cost of Hal’s end-run. In the season 3 trailer setup, Hal later tells Grace,

“I thought I was warning the commander in chief he had a rogue deputy — which he did.”

A line that tees up accountability as the new battlefield. Grace enters the new season as POTUS with a secret that can break her. Kate remains Ambassador, implicated by knowledge and proximity, yet still a viable vice-presidential option in a capital suddenly short on stability. Dennison cools the romance and goes back to safeguarding what he can inside Whitehall. Trowbridge survives the scandal for now while Roylin lives to bargain. Stuart grieves for Ronnie and hardens around the work. Eidra’s quiet tradecraft keeps doors open that politics would slam shut. The frame is set. The Diplomat season 2 has moved every piece so that the constitutional crisis is personal, and the special relationship is at stake.

Stay tuned for more updates.