Dean is infected with an illness that starts as anxiety, but moves to full-blown terror that stops the heart. Sam and Bobby (Jim Beaver) must find the root before Dean dies.

Sam and Dean investigate the mysterious deaths of several men who apparently dropped dead of fright. They visit one of the victims in the morgue, and Dean becomes infected with the illness which starts as a general anxiety, then moves on to full-blown terror that eventually stops the heart. Sam and Bobby (recurring guest star Jim Beaver) must find the root of the disease before Dean dies and is sent back to Hell.