After 24 hours of screen time,  Castle season 5 comes to a close with an aptly titled finale, “Watershed,” paving the way for whatever lies ahead for Castle (Nathan Fillion) and Beckett (Stana Katic) in season 6.

For a season finale, the episode spends more time on the case aspects of the show than it does dragging out the characters’ drama – then again, maybe that’s the point.

Either way, the finale opens with an anxious Kate Beckett awaiting her interview with Anthony Freedman (Kyle Secor), the Deputy Director of the FBI and the man in charge of her interview for the special task force job she was offered last week.

Sensing her hesitation, he gives her the opportunity to end the interview, but she sees it through, leaving her fate in his hands. Jet-setting back and forth to DC makes her late to the crime scene, but when Castle asks where she was, she blows him off and focuses on the case.

For his part, no alarm bells are going off in Castle’s head yet, mostly because he’s dealing with his own anxiety about an upcoming school trip to Costa Rica that Alexis (Molly C. Quinn) is planning to take. He’s hesitant because of what happened in Paris, whereas Alexis wants to go in order to help herself move past Paris and not live in fear. It will take him almost the entire episode to write the check for her, but by then, he’s got a much bigger issue on his mind.

At around the halfway mark, Beckett’s boarding pass slips from her jacket to the floor in front of Castle, and from that point on, she’s got some ‘splaining to do. According to him, he’s more upset by the fact that she lied than that she’s thinking about moving up in the law enforcement world, but clearly he’s not too keen on her taking the job either.

As far as Kate is concerned, this is a job she’s always wanted and it has no bearing on their relationship status. There’s no explosion of emotions on either side, but Castle does put some space between them and they remain on shaky ground from there on out.

Amidst all the emotional turmoil is the case of a murdered Harvard honors student, Erika Albrook, a young woman found dead in the water tank of the seedy motel she was staying in. It takes a little bit of sifting since Erika had decided to invent a false persona at the hotel while letting her parents think she was backpacking in Europe, but the team eventually reveals that Erika was looking into the death of a friend by hacking into the files of a local law firm.

Banks & Bauer has a number of upscale clients, all of whom make them less than helpful when it comes to divulging information that could lead to a murder suspect. Still, Beckett and Castle are relentless, hitting the case from all angles until finally a name emerges.

Unfortunately, someone gets to former Banks & Bauer lawyer, Ian Blaylock, before they do, but the clues point to one of his clients. When Beckett has a chat with him, she’s certain of his guilt. All it takes is locating the wealthy man’s sleazy half-brother – along with a nice speech from Beckett about not lying to her – and his fate is sealed and the case is closed.

The entire episode builds up nicely to the final scene. There are meaningful conversations between Kate and her father as well as Castle and his mother. Castle and Kate’s relationship is explored from both characters’ point of view, as is the importance of this job opportunity for Kate. Both of them have been stalling on the issue of the ultimate trajectory of their relationship; both have to decide whether it is fear or prudence that is holding them back. So by the time the call comes confirming that the job is hers if she wants it, they are both ready for a serious chat.

Ironic that the fate of their relationship is decided on a swing-set at the park. Kate issues an apology; Castle, a ring and a question. Will she say ‘yes’? Should she? Can she have the dream job and Castle, too? Is Castle willing to take whatever answer she gives? How ready are they for this next step?

Only time will tell and fans will have an entire summer to speculate.

Castle returns for season 6 in the Fall on ABC.