The second part of the premiere episode of "Castle" will shed light to Kate Beckett's (Stana Katic) disappearance in the upcoming season of the ABC series.

Spoiler TV reports that while the first of the two-part season opening will concentrate on Richard Castle's (Nathan Fillion) point of view, the second episode titled "XX" will be told entirely via Beckett's. In the synopsis released by the network, bits of why she suddenly became missing are finally being revealed. After receiving an anonymous tip warning her that several mercenaries are on her tail, Beckett has no choice but to run to lead the danger away from her family.

In the trailer, she can be seen running away from Castle after telling him she loves him. Viewers also see her kick some ass while fighting for her life. What and why they are after her, however, remains a mystery. Meanwhile, Castle is abducted by an unknown group, which is now revealed to be the same mercenary team who is after Beckett. The kidnappers threaten Castle that they will kill him if he does not divulge where his wife is hiding.

According to the website, "XX" will run concurrent to Castle's timeline, while he, Kevin Ryan (Seamus Dever), and Javier "Javi" Esposito (Jon Huertas) are looking for Beckett. In an interview with TV Line, showrunners Alexi Hawley and Terence Paul Winter talked about their use of multiple perspectives to tell the series of events in the premiere.

"For us what's great is you set up the mystery of what the hell has she [Beckett] been doing, and then you get to go back and watch it happen, and it's not exactly what you thought. It's fun when little things like that force you to become more creative, and it ultimately paid off with dividends," they shared.

"Castle" returns on Monday, Sept. 21 at 9:00 p.m. EST on ABC.