Rick Castle and Det. Kate Beckett unexpectedly end up on a cruise ship together in Season 8, Episode 8 of "Castle," entitled "Mr. and Mrs. Castle," and it appears anything can happen.

While the duo are busy snooping around a cruise ship in their investigation of an entertainer's murder, the boat set sails, stranding them at sea. Desperate to rekindle his wayward relationship with his estranged wife, Castle (Nathan Fillion), doesn't seem all that perturbed by being stuck aboard the ship.

"I think your crime scene is making a run for it," TV Guide reports he jokes with Beckett (Stana Katic), before tauntingly shouting, "I'm king of the world."

The extended time together comes after the couple's passionate reunion marking their one-year anniversary, which played out at the end of Episode 7. At that moment, the couple declared "a time out from the time out."

With confetti and balloons flowing in the background, Castle left little doubt where his heart was, insisting to his wife that he has never lost hope that they could find their way back to one another.

"Not since the day we met," he said. "And that will never change until you tell me it should."

The "Mr. and Mrs. Smith" episode has long been billed as critical to the remainder of the season, not to mention the ongoing, long-term relationship between the headstrong co-stars.

"You can read into that a little bit," co-showrunner Alexi Hawley recently told TV Line of a scene in a past episode in which Castle intimately sniffs his wife's T-shirt. "That's a really powerful last moment that shows you that all that love is still there."

The new episode airs on ABC Monday night at 10 p.m. ET.