As the final episode of "Castle" Season 7 and perhaps the entire show draws to a close, Seamus Dever's character Ryan has a dilemma on the upcoming episode that just won't let him rest.

During Monday night's airing of Season 7's 18th episode and the show's 150th overall, CarterMatt.com describes him as "focused to an extreme level" on the circumstances surrounding a shooting while he was working security detail for a decorated politician.

The website adds, "The situation has left him more motivated than ever to get this right." That's where Espositio comes in, with Ryan talking his ear off throughout the episode about the course and direction of the investigation.

Meanwhile, showrunner David Amann recently described the upcoming final episode to TVLine.com as "compelling, high-stakes story-telling." Amann later added writers are planning to make it a "buoyant, classic episode."

All season long, "Castle" writers have seemingly been intent on developing a new mythology that revolves around Castle and his disappearance on his wedding day during the Season 6 finale. TVLine predicts writers are likely to more closely revisit that mythology as the season nears an end.

In Monday's episode, titled "At Close Range," Ricardo Chavira plays the role of congressman Alex Lopez, and Reiko Aylesworth plays his wife, Mia. The episode also introduces David Conrad as his brother-in-law Frank and Heather Mazur as his sister Gwen.

TVLine adds Ryan's part-time security job is with his brother-in-law's private security firm. The shooting in question is slated to take place at a charity event attended by the congressman.

The ABC-aired show premiered in March of 2009. Creators have not revealed if the show will be returning for another season. The show also stars Nathan Fillion as Richard Castle and Stana Katic as Kate Beckett.