This post contains spoilers from The Diplomat season 3 episode 7 from this point forward.
The previous episode delivered quite the jaw-dropper as Trowbridge went rogue and placed the full blame of the carrier attack on the late President Rayburn. The Diplomat season 3 episode 7 kicks off in the chaos of the Trowbridge's worldwide admission of Rayburn's guilt. The Penn administration scrambles to put together the president's reaction to the news. Hal wants them to double down.
Rayburn's name has been dragged through the mud and protestors are assembling on the streets. Kate hides in the backseat of the car as she receives a call from Billie to relay the message that Penn's prepared to counter with Roylin's involvement. Kate refuses to hide from the protestors and stand down from doing her job as ambassador just because she's the Second Lady.
Stuart asks Kate what happened and what went wrong, since he understands Roylin masterminded the attack. She doesn't tell him the truth, but she does confirm that Rayburn was involved. (He wasn't, but he needs to be as far as Stuart knows.) Kate sneaks Callum onto the property, and he informs her that they found the submarine. There were no survivors, but Trowbridge won't allow the US near it.

Callum reveals a major threat to national security
Because it's not safe for Callum to leave Winfield without being seen, the end up having a meal that's basically a date. Since they're alone, Kate and Callum decide to take advantage of their privacy and have sex. Honestly, good for Kate for finding a moment for pleasure in the midst of constant chaos. Stuart tells Kate that he can't get her a meeting with Trowbridge. London is icing out America.
The White House wants Kate to make a statement to the world in the event that she can't secure a meeting with Trowbridge. She and Callum disagree about how to proceed with this matter. Hal isn't excited to hear that Kate has been turning to Callum for advice on the situation, especially since he doesn't want her to make the statement. Unfortunately, Trowbridge turns down the meeting.

Kate learns that Trowbridge could be turning to China for help with the Russian submarine. With that information, Kate insists to Billie that Penn should apologize to Trowbridge. Billie doesn't believe the threat is real enough for Penn to have to do that. Callum pushes Kate to call Hal to convince him to do something. He warns her that China can't get to the submarine because it's carrying Russia's weapons. She finally gets through to Hal and Billie and they believe that the threat is real.
Callum still isn't satisfied with how America will proceed with this matter, which causes an argument between him and Kate. He reveals that he was a soldier when he was 19, and that's where his frustration comes from. The conversation continues and Kate realizes that Callum's just another version of Hal since he held information about a problem and then made it hers. There's probably no coming back from this fight between Kate and Callum.
Billie instructs Stuart to get a lawyer with what could be coming down the pipeline. Hal speaks with Billie and admits that he and Kate are separated and only married to the public. Callum tells Kate that Penn called Trowbridge to propose a bilateral summit, which he accepted. Meanwhile, Callum isn't sure if he's "done" with her after their fight. She worries that she doesn't treat people the way they deserve and asks for another chance. Callum simply nods.