Danny and Baez investigate a possible serial killer who sends a chilling message to Danny. Erin toys with the idea of applying for a judgeship. Frank is in a bind when mayoral candidate, Katherine Tucker accuses him of secretly investigating her husband. Eddie faces her estranged father when he winds up in the hospital.
Elenco: Tom Selleck , Donnie Wahlberg , Bridget Moynahan , Will Estes , Len Cariou , Sami Gayle , Marisa Ramirez , Abigail Hawk , Vanessa Ray , Gregory Jbara , Robert Clohessy , Andrew Terraciano , Amy Carlson , Jennifer Esposito , Steve Schirripa .