When an emergency keeps Marge from taking Lisa to an about-to-close museum exhibit, Lisa tries to take the bus instead and ends up in an unfamiliar part of town.

!! Tropes:

* AnAesop: Never be afraid to live life on the edge.
* AdultFear: Lisa being missing.
* {{Area 51}}: Or rather, Area 51-''a''.
--> [[NoSuchAgency "You are here. We are not."]]
* BaitAndSwitch
* {{Balloonacy}}: Subverted when Homer needs to get up high to spot Lisa. "Oh, I hope this works...these are for you if you let me use your cherry-picker."
--> "Well, I've already got some balloons - but they're not this nice. Deal!"
* BilingualBonus: The signs in the Russian district of Springfield are actual Russian words.
* IfIHadANickel: Dr. Hibbert subverted the trope. He replaced "a dime" with the amount of money he usually charges for the kind of medical procedure performed on Bart.