This week on Castle‘s winter premiere, three proved to be very much a crowd when Rick’s ex-wife Meredith came for a visit. But was it what the Deep-Fried Twinkie left behind — a question in Kate’s mind — that will ultimately pull a thread and unravel Caskett?

Kate staying at Rick’s because her place is being fumigated? Nice. Meredith crashing there to tend to sick Alexis? Not nice. And whether Rick should have permitted it was the recurring topic. Kate contended to Rick that she have given him “her look” when she claimed to be OK with the arrangement, while Lanie warned her gal pal that, given Rick and Mer’s history of “ex sex,” she needed to mark her territory: “This is a war, and you are losing.”