Mysteries abound when pallbearers at a funeral lose control of a surprisingly heavy casket only to have a second unknown woman tumble out along with the original deceased. When Castle and Beckett learn that the victim was a doctor at County Hospital, their investigation takes them into the world of amorous, bed-hopping physicians. Did jealousy turn to murder, or did the doctor's mysterious work outside the hospital lead to her demise? Meanwhile, Castle's relationship with Gina is challenged when she tries to bond with Alexis.