On The Mysteries of Laura episode “The Mystery of the Unknown Caller,” Laura’s (Debra Messing) younger sister Lucy shows up in town. The reunion isn’t planned or really welcomed. Lucy is a suspect in a murder investigation in Brooklyn. After Laura runs after and tackles her sister, the two reheads sit down for a chat. “You’re so good at this policing thing,” the younger one says with sarcasm. Nonetheless, Laura pledges to save her sister (with a pinky swear!).
Lucy Diamond is portrayed by Debby Ryan. The 22-year-old actress is best known for her roles on Disney Channel’s Jessie (Jessie Prescott, the young nanny living in New York City) and The Suite Life On Deck (Bailey Pickett). The Mysteries of Laura airs Wednesdays at 8pm on NBC.