Break out your Season 1-3 DVDs and start looking for clues, Castle fans, because someone we haven't seen at all this season will be returning to our small screens sometime during May sweeps, according to TV Line.

But who?!

Well, there's always the ever-elusive Triple Killer (3XK), whose return show creator Andrew Marlowe hinted at last month when he told TV Guide that producers were “in talks" about whether to write him back in.

But Marlowe was also a bit tentative, saying that a 3XK return would hinge greatly on an official Season 5 renewal, which we're unfortunately still waiting for.

Other options on the table are Hal Lockwood or Roy Montgomery (our money's on a flashback scene, unless you believe the whole conspiracy theory that they're still alive), Kate's father Jim Beckett, or Castle's exes, Gina or Meredith.

Are we missing anyone? Tell us which character you think will be making a surprise return before the Season 4 finale in the comments below!

Source: TV Line


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