After overhearing a conversation about a sick baby, House investigates the maternity ward and predicts an epidemic. After realizing the severity of the disease, Cuddy quarantines the maternity ward. In an effort to discover the source of the epidemic, House begins treating the children. However, when the kidneys of two of the children shut down, House is forced to test which drug caused the failure, resulting in one of the babies dying. Following an autopsy, the team discovers the presence of Echovirus 11, CMV, and Parvovirus B19 antibodies. They test the mothers and decide the cause of the epidemic is the Echovirus. Using an experimental anti-virus, they successfully cure the remaining babies. House, determined to find the entry point of the virus, finds an elderly hospital volunteer coughing and wiping her nose as she pushes around a cart of baby toys and blankets and makes the connection.