Serenity Valley Convalescent Home
Serenity Valley Convalescent Home is a nursing/hospital facility which is located in Davenport, Iowa.
Celeste was a patient of this nursing home.
Doctor Green is actually a Horseman named Pestilence pretending to be a doctor in order to experiment on patients. Before infecting Celeste with multiple deadly diseases, he tells her that she's his "favorite patient". Doctor Green's assistant helped Doctor Green (aka Pestilence) by watching for Dean and Sam. She also managed some other patients.