The BAU is called to investigate after the bodies of missing people are discovered in a remote region of the Idaho wilderness.
Ted and Barney go to the same Halloween party they go to every year where Ted looks for his lost love, the Slutty Pumpkin.
House treats a young married couple with similar symptoms, but they are shocked by the cause of the illness; a walk-in patient (David Morse) stands up to House.
The team suspects colleagues when the remains of a young Jeffersonian intern are found in the building's incinerator; Booth poses as Cam's boyfriend and accompanies her on a family get-together.
Melinda must contend with crash investigators and an evil spirit when she tries to help hundreds of confused passengers killed in a jetliner crash.