Castle | Throughout the intensity of “Kill Shot” and the flirty fun of “Cuffed,” one can’t be blamed for forgetting that there are still a pair of potent secrets being kept — that Rick purposely waved Beckett off the unsolved mystery of her mother’s murder, and Kate remembers Rick’s season finale “I love you.” Castle’s secret “will resurface” by season’s end, series boss Andrew W. Marlowe tells me. And at the worst possible time, might we assume? “Well, we wouldn’t be dramatists if it came at the best time,” he answers with a wink. “And I will tell you that it will have an impact on their relationship.” Want a scooch more angst, Caskett ‘shippers? Well here it is: “Beckett’s secret might resurface even earlier,” Marlowe teases.