Nathan Fillion Nathan Fillion

During Castle's recent two-parter, Rick's former muse dropped a bombshell just before she was seemingly killed.

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"I think [Castle] is evaluating whether Sophia was telling him the truth," creator and executive producer Andrew W. Marlowe tells "He doesn't have any way to really access it. So he is trying to figure out how to follow up on it, but I am not sure that he knows how."

That said, Marlowe says viewers will eventually get to see Castle pursue the possibility. It just may not happen anytime soon. "We are planting seeds for further storytelling assuming that we get good news on Season 5," he says, noting that the story might surface once more this year. "I haven't decided yet, but it is something I absolutely wanted to bring up. He is going to pursue it, but it is not something that he is going to pursue immediately. I think that he is still wrestling with it."

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