Credit: Richard Cartwright/ABC Photo: Beckett and Castle Smirk in Castle Season 6, Episode 3, “Need to Know”

As a super successful mystery writer, Castle (Nathan Fillion) has legions of adoring fans, but on next week’s episode of Castle one such admirer — who also happens to be a known killer — takes things a bit too far when she’s taken several people hostage and wants only to interact with the writer himself.

“She is demanding to speak to only you,” Captain Gates says begrudgingly.

By the looks of the promo for Season 6, Episode 4: “Number One Fan” below, Castle goes in to speak with the killer, by that’s when things get dicey.

“I want you to prove my innocence,” the gun-toting assailant cries.

After Beckett tells her boo that the suspect is “unstable” all we see is the killer firing a gun, quickly followed by another shot of Castle, who is rocking his bulletproof “WRITER” vest, flying backwards through a glass window.

Check out the complete promo below to see this tension for yourself!

Castle Season 6, Episode 4: “Number One Fan” airs on October 14 at 9 p.m. ET on ABC.