Homer becomes the most popular person in town, when he gets an illegal cable hookup. But Lisa doesn't approve and fears that Homer will go to hell for violating the Eighth Commandment ("Thou shalt not steal").
The episode begins in 1200 B.C., where the Jews, having fled Egypt, make a camp at Mount Sinai. A Jew named Homer the Thief (who bears a striking resemblance to Homer Simpson except he has a full beard) steals from an adulterer and idolater. Moses appears, claiming the Ten Commandments. When told "Thou shalt not steal", Homer the Thief says "D'oh", then the scene forwards to present day, it all having been a dream of Homer Simpson, who was snoozing in the hammock.
After observing Ned Flanders reject an offer to get an illegal cable hookup, Homer chases after the cable man and wants to be hooked up for free. He likes the new channels he gets, which the family watches with him. However, Lisa feels anxious. Following a Sunday School lesson regarding the existence and nature of Hell, Lisa becomes terrified of violations of the Ten Commandments, the adherence to which she is assured will keep one's soul safe from Hell, while Bart becomes amused by repeating the word "Hell" on the car ride home. At home, Lisa imagines her house melting, and the devil sits at their couch with them. He tells her that watching television will cost her nothing but "her soul". She fears that because Homer violated the Eighth Commandment (thus "Thou Shalt Not Steal" according to the division by the Anglican and Reformed Churches), he will go to Hell when he passes on. She additionally opposes other examples of common and harmless thievery, including her mother's tasting of grapes in a grocery store which she has not paid for. Lisa pays a visit to Reverend Lovejoy at church, where he suggests that Lisa cannot turn her father into the police (as she must "Honor Thy Father and Thy Mother*), and instead encourages Lisa not to watch anything on Homer's cable hookup, setting a good example.
Homer invites his friends from the power plant, as well as Apu, Moe and Barney to watch "The Bout to Knock the Other Guy Out!", on the pay-per-view movie channel The Blockbuster Channel. (Mr. Burns and Waylon Smithers come as well.) Meanwhile, Bart has set up posters on the back door for his showing of the adult-only channel "Top Hat Entertainment" for 50 cents (although his age requirement is 8), but is caught a few seconds later by Homer. Homer's conscience eventually bothers him, more so in the form of his daughter's distress than a moral objection to stealing cable, and he gives in to Lisa's protests, begrudgingly choosing not to watch the bout. Marge and Maggie join them as well. Bart, on the other hand, plans to go back to watch the fight, but Homer forced him to stay in his room. Homer sits the match out and when it is over, he hesitantly (and unprofessionally) cuts his cable hookup, despite Bart's objection. He accidentally (somehow) cuts the electricity to all of Springfield in his random wire-cutting, before finally cutting the cable wire, abruptly ending the episode with static showing onscreen.