Richard Castle: Twin girls are born and put up for adoption. Odette goes to a wealthy, loving family, Barbra, not so lucky. She gets bounced around from one foster home to the next, always knowing, deep inside, that she was meant for something better. Then, one day, the two of them meet on a train bound for Miami. The connection is instantaneous. In two days they learn everything there is to know about each other. And Barbra can't help but think, "If only I had landed in the lap of luxury like Odette, I could have been anything I wanted to be."
Kate Beckett: Are you suggesting that Barbra purposefully caused the derailment to take over Odette's life? With what? Her crazy Wiccan powers?
Richard Castle: [excited] Oh... Wow! That would be an incredible twist! But no. No. The accident happens, Odette is killed, Barbra survives. And in the midst of all the chaos and rubble, she sees her chance. She switches identification with Odette, and she changes her destiny. In one move, Barbra builds herself a better future. A perfect life.
Kate Beckett: Until she was murdered a year later.
Richard Castle: Yeah, well, separated twin stories never end happily.
Richard Castle: Except 'The Parent Trap'.