In Plain Sight - Season 3 Episode 4 -

Mary and Marshall try to help FBI Agent Mike Faber convince his informant to enter WITSEC. Despite their best efforts, the informant refuses their protection and gets himself into a heap of trouble. After Mary, Marshall and Agent Faber save the informant from certain death, he and his family join Witsec. Meanwhile, Stan has to deal with an ex-boxer/witness suffering from pugilistic dementia.