It's all about family these days for Rick Castle.

On last night's emotional "Target," the author faced every father's worst nightmare, as Alexis was abducted and Castle started a frantic search for his daughter.

Next Monday, that search will come to an end... but not before Rick learns the biggest secret of his life. It's summed up in the three final words of the ABC teaser below. I'm your father.

Oh yes. Watch this promo for the most significant episode of Castle Season 5 to date:

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.