Ike accidentally walks in on his adopted parents having sex, with Gerald dressed up as a UPS delivery man. Ike tells Kyle, who thinks his mom is cheating on his dad. He tells his friends, and word eventually gets out to the men of South Park. They decide, after getting word from an old man who told a cautionary tale about the milk men of old, to deal with the UPS man themselves. So they dress up in Bane masks, and beat him up, but can't kill him due to onlookers discovering them.
This starts a rash of security systems being installed in South Park as people fear for their lives from a gang of Banes. In order to make some more money, a personal security system called "InSecurity" is introduced, which goes off when a person is scared. Eventually, after Kyle and the rest of the town corner the UPS delivery man and make him accidentally commit suicide, they think the danger is over, until the old man warns them about the door-to-door home security workers, and everyone busts out their Bane masks one more time.