The popular onscreen power couple, Richard Castle (Nathan Fillion) and detective Kate Beckett (Stana Katic), might go through the most difficult time in their lives in episode 2 of "Castle" season 8 titled "XX". But before that, the creators will give fans a glimpse of the situation in the premiere episode titled "XY".

The crime drama will begin by introducing a career change for the detective and will gradually take viewers through an explosive chain of events set by a mysterious stranger. While episode 1 will narrate the incident through the eyes of Fillion's character, episode 2 will focus on the new captain's perspective.

The official synopsis of the second sequel states that Katic's character will receive a mysterious tip from her past and it will launch her into a fight for life with a team of mercenaries hot on her trail. As she tries to figure out who wants her dead, Richard will investigate why his wife is on the run.

Executive producer Terence Winter has already teased problems for the power couple in season 8. "It's much different when your wife is the captain, the boss, versus when your wife is the detective," TV Guide quoted him as saying.

However, "Castle" fans will have to wait until 28 September to find out if the mystery novelist will help his wife in solving the mystery.

Meanwhile, they can tune in to ABC at 10pm on Monday, 21 September, to get a glimpse of the incident in the premiere episode of season 8 titled "XY", which will be live streamed here.