Episode - 7F16\\
First Aired - 2/21/1991

After suffering a heart attack at the movie theater, Grampa realizes his mortality and lets Homer in on a dark family secret: Homer has a half-brother named Herb (the product of a one-night stand Grampa had with a dunk-tank carny-cum-prostitute) that he gave up for adoption before Grampa married Mona. When Homer finally finds Herb's whereabouts, the Simpsons are off to Detroit, where Herb recruits Homer to create a car for his company.

See the [[YMMV/TheSimpsonsS2E15OhBrotherWhereArtThou YMMV]] page for details.
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* {{Bowdlerization}}: Bart singing the word "bastard" after justifying his use of it was edited out when shown on UK TV.
* BreadEggsBreadedEggs: For their day out, Bart wants to go on a boat ride, and Lisa wants to go on a pony ride. Cut to Lisa riding a pony on Herb's yacht.
* ComicallyMissingThePoint: The man in charge of the orphanage who Homer meets looks like Dr. Hibbert and told about a lost twin and he fails to notice a connection. Also, he fails to get the enormous repeated hints at where his brother is the man drops and has to be directly told he is in Detroit.
** After Homer told Herb that they're brothers, he's in shock. But Homer thought he lost the connection.
* DownerEnding: Homer is left heartbroken after a bankrupt Herb disowns him. Some fans were so upset by Herb's downfall that the producers would ultimately do [[Recap/TheSimpsonsS3E24BrotherCanYouSpareTwoDimes "Brother, Can You Spare Two Dimes"]] to give Herb a happy ending again (though a much later episode ["Changing of the Guardian"] reveals that Herb went broke again, and viewers don't get any information as to what happened).
** Though the commentary also reveals the original ending had Herb coming up with another idea as the bus pulled away.
* {{Flashback}}: A quick one explaining how Abe had Herb. Quickly followed by Abe marrying Mona and the birth of Homer. (Incidentally, this is the first time Mona ever appeared.)
* IdenticalTwins: The head of Shelbyville Orphanage looks like Dr. Hibbert and said he has a [[LongLostRelative lost twin]].
* MeanBoss: Herb is extremely dismissive and temperamental to his employees, viewing them as privileged idiots (in stark contrast to [[SelfMadeMan his own upbringing]]). [[HoistByHisOwnPetard This ends up his own undoing]], as he refuses to take their warnings of Homer's incompetence seriously, and forces them to continue with his doomed project until it's too late.
* NeverMyFault: Herb blames Homer for ruining his company despite putting him in charge, shelving all other projects and outright ignoring his employees' (who despite being 'privilaged idiots' as he put it still know enough about business to be on the board of a car company) warnings.
* RichesToRags: Herb thanks to Homer.
* SelfMadeMan: Herb.
* SpecialGuest: Danny [=DeVito=] as Herb Powell
* TitleDrop: Homer when he goes to the Shelbyville orphanage and thinks it's been replaced with a gas station. (Then he learns it just moved across the street.)