Complete story — includes the ending
Sam wants to see Melinda doing her thing, and follows her to a school where he's been doing work. Mel quickly sees ghosts and works out that they are patients of the mental hospital that the school used to be. One ghost in particular needs her help, she was admitted to the hospital after supposedly drowning her baby. Sam goes into the tunnels with Melinda, and gets freaked out when she has a vision of how the ghost died, which involved electro-shock therapy. Delia and Eli work out that the ghost's doctor was a ghost himself, and she is trying to protect the children in the school from him. Mel finally tells Sam about him being Jim, and he refuses to believe it, instead thinking that Mel needs professional help.
Sources and content license
Source and revision history · Adapted from Wikipedia contributors, Ghost Whisperer season 4. HTML formatting and reference markers removed. · Content license