WARNING: Castle Season 6 major spoilers ahead!

Castle season 6 is almost halfway done. But, a lot of fans are still guessing what would be the big story at the later part of the season.

Before the mid-season finale ended, fans were shocked to learn about Dr. Neiman's (Annie Wersching) connection to 3XK.

While it is still not confirmed whether Dr. Neiman is 3XK aka Jerry Tyson's lover, the event lead to several speculations about 3XK and his possible connection to Beckett (Stana Katic).

[Remember the end of the episode wherein Beckett was teary-eyed after hearing the song stored in the flash drive left by Dr. Neiman?]

The song "We'll Meet Again" got fans talking as to what its connection to Beckett. Could it be 3XK's way of mocking Castle and Beckett for his return? But, then again, how come Beckett was more affected than Castle considering that Castle was the one kidnapped by 3XK?

While no confirmations have been made yet, several hints got Castle fans wondering.

Yesterday, TVGuide gave viewers some hint on what's to expect this season of Castle.

When asked about the two-parter episode this coming February, TVGuide reported that Marlowe confirmed there's not going to be a two-parter episode.

"We're going to forgo tradition," executive producer Andrew W. Marlowe says.

TVGuide also mentioned an upcoming "big" episode that will deal with Beckett "mythology." TVGuide also speculated that this could be connected to Beckett's mother's history.

If the report is true, could Beckett's and her mother's history finally be dealt with?

There are no confirmed news yet or even rumors as to how Beckett and her mother's death will unfold. However, Castle writer and consulting producer Terri Miller recent interview with Emertainment Monthly might shed some light.

Emertainment Monthly asked Miller, "3XK left a pretty sinister note in song form for Castle and Beckett at the end of "Disciple"; are plans in the works to bring that storyline up again any time soon, or to bring back Michael Mosley for the role?"

Miller responded, "3XK is insidious and pops up when you least expect it. I wouldn't turn your back on him."

Could this be a major hint that 3XK will come back?

Tell us what you think!

Castle airs every Mondays on ABC at 10/9c.