Well, that was unexpected.

Let’s find out what happened on this week’s Castle, “Mr. and Mrs. Castle,” and the fall finale had plenty of things to talk about.

In the cold open, our victim floats up from under the surface of the River Hudson and an innocent bystander finds the body. Queue Beckett and the gang to investigate while Castle recruits Hayley to look into the mysterious text Beckett received and to see where it came from and from whom it was received.

The victim is a Jane Doe, who worked on a cruise ship as a jazz dancer, based on her outfit. In the morgue, the pathologist finds a bag of uncut heroin in the victim’s mouth, attached to floss.

Beckett goes to the cruise to investigate and, lo and behold, there’s Castle screaming, “I’m king of the world!”

It’s a truth, universally acknowledged, that this must be screamed at the top of your lungs whenever you are on a boat.

Castle knows.

So, he tells Beckett he’s there to help with the case and as she believes it’s connected to Vulcan Simmons and LOCKSAT, she tries to get him to keep out of it.

Then the cruise ship starts to move, and Beckett’s crime scene is floating away with her and Castle still aboard.

She and Castle have an hour to find the murder scene weapon and murderer. The crew have been told not to cooperate, and then they will be outside the laws of the land and in International waters.

Of course, there’s still time to talk about their anniversary reconciliation between the sheets.

As you do.

Castle then has a fantastic dance number, and Nathan Fillion shines, as always, in his role of goofy lovable rogue, while Beckett chats to the gossips on board.

They then discover that our victim hid things on the ship, and discover a camcorder in the lifevests on board, with video footage of heroin being loaded onto the ship.

Castle finds the man from the video and chases him on foot before bringing him in for the murder of our victim.

His lawyer, Caleb Brown, gives a plea deal of second degree murder and a recommendation of a reduced sentence. Beckett says she’ll consider it.

More on him later.

Vikram and Beckett are running their investigation from a strip club, and Beckett is still obviously thinking about her anniversary night with Castle.

Castle is also thinking about it, and then he has Hayley hack Beckett’s phone to find out where the encrypted message came from. They realise she and Vikram are working on the LOCKSAT case, and Hayley breaks into Vikram’s firewall while Castle utters sweet nothings into Beckett’s ear.

Hayley and Vikram get into a hack-off, where Hayley cyber-loads him with cat videos—a tie for best sight gag of the episode, drawing with Castle’s Jazz hands—and is cyber-nuked by Vikram.

Castle is angry. He confronts Beckett at the precinct, and she knows he knows. He asks why she didn’t tell him, and why she broke their marriage when he could have helped her, and they could have been together in secret.

She says she didn’t think about it because she was trying to protect him, and Castle seems visibly hurt.

Ryan and Esposito—Espo is wearing a suit for the entire episode, and it seems so strange, although it was a nice suit—track down the other drug runner and the murderer’s accomplice at his apartment. Ryan, Beckett and Espo give chase and when the perp pulls a gun, the boys shoot him down while Beckett looks on, forlorn.

Vikram cheer her up with the news that the lawyer, Caleb Brown, is in cahoots with the drug runners and they now have aa link to LOCKSAT.

Beckett appears at Castle’s door, as he is having a drink with Lucy, his talking pyramid (voiced by the wonderful Aubrey Plaza). Beckett tells him he was right, they could have pretended to be broken up but still together. Castle seems hurt, and asks if she thinks it would be that easy. Beckett says she’s sorry, and Castle accepts it and sweeps her into his arms.

The break-up arc is over guys.

Whoop.

Castle will be back in January, so we have time to think about what these crazy kids will be up to.