"Castle" season 8 returns next month and apart from the expected more secret romance from Kate (Stana Katic) and Rick (Nathan Fillion), fans will finally get the answer to the mystery of Rick's disappearance.

Avid followers of the drama comedy series know very well that Rick went missing back in season 7, but when the show was picked up for another reason, it wasn't explained well why.

TV Line spoke with "Castle" showrunners Alexi Hawley and Terence Paul Winter to ask about this mystery and the latter confirmed that the reveal is happening. "Here's a promise: We are going to conclude that. It will be done."

In that particular episode, fans will not only know the reason Rick went missing, but also follow him, Hayley (Toks Olagundoye) and Alexis (Molly Quinn) to Los Angeles, as they pursue a case. There will also be a reunion with Fillion's "Firefly" co-star Summer Stau, who guest stars in that episode.

Meanwhile, as previously reported, Kate and Rick, who reunited at the end of the first half of the season, will come back and pretend that they have broken up. Hawley also teased that there will be a "lot of lost time to make up for."

When they are not together on their secret romance, they'll continue solving cases, and for the first time, the couple will join a courtroom.

TV Line also mentioned that the team will visit the police academy where Kate used to train. The particular episode will be the series' 15th. "Californication" star Ellen Woglom appear as guest in the episode, and play as a cadet who served as Kate's mentor.

Also coming in "Castle" season 8 is an action-packed episode featuring a Russian agent portrayed by "Spartacus'" Nick E. Tarabay. "We have a diplomatic security agent from Russia who comes, because there is the death of a Russian national. He's a big character," Hawley revealed to TV Line.

"Castle" season 8 returns to ABC on Monday, Feb. 1, at 10 p.m. EST.