On the Lam is an episode in the Hey Arnold! TV Series.


Stinky, Harold and Sid are on the run after they think they blew up the police station.


Mr. Simmons shows his class a rocket-launching experiment with baking soda and vinegar. Harold wants to launch the rockets, but the bell rings before Mr. Simmons can supervise the proportions. Harold, Sid and Stinky then sneak into the classroom and steal all the rockets, baking soda, and vinegar from the science closet with Stinky also bringing his Louisiana hot sauce. Using Stinky's hot sauce with the other ingredients, they launch the bunch of rockets into an old police station building just as Ernie dynamites and blows up the building--however, not noticing Ernie and his construction workers, the boys believe that they blew up the police station and panic.

They run into Arnold's basement and try to hide there, but Stinky accidentally reveals what they did to Arnold, and they devise a plan:

  • Plan A is to get to the trainyard and hop a boxcar to go down south and live with Stinky's grandmother.
  • In case they can't find Stinky's grandmother, Plan B is to disguise themselves and become hobos.

Arnold believes they should go to the police and find out what actually happened so, Harold ties Arnold up and gags him to stop him from ratting them out. When Stinky, Harold and Sid's parents discover that the boys are missing, they get really worried (especially Harold's mom).

On the way to the trainyard, Harold, Stinky, and Sid encounter multiple cops in the process while Phil leaves Arnold to his game of secret agent. Eventually, Arnold frees himself by hopping up the stairs and explaining to Grandpa Phil and Ernie about what happened to Harold, Stinky and Sid and their plan to become hobos. Ernie tells Arnold that Harlold, Stinky and Sid didn't blow up the police station, he did with his construction crew (he also states it had been slated for demolition for months). Arnold convinces Grandpa and Ernie to go with him to the trainyard to stop the boys and clear up the misunderstanding. 

Harold, Stinky, and Sid make it to the trainyard and encounter real hobos after ditching their costumes. Their parents, Arnold, and the police manage catch up with them scaring them out of the train car. They manage to get onto the roof of a train car, but several spot lights shine on them. They decide to give up as they are cowards. Harold, Stinky, and Sid sob, saying that they didn't mean to blow up the police station and that they didn't mean to hurt anyone and it was a harmless prank.

Ernie corrects them by revealing the truth: he and his workers demolished the station, not the boys. Harold's mom is relieved to have him back and hugs him tightly. With the entire misunderstanding cleared up, everyone has a good laugh. But then Mr. Simmons comes in and, after explaining that he had seen the whole thing on TV, tells the boys that they will be punished for stealing from the science closet, much to Harold, Stinky and Sid's dismay.



  • When baking soda (sodium bicarbonate, NaHCO3) and vinegar (acetic acid, CH3CO2H) come into contact with each other, a great deal of carbon dioxide gas (CO2) is suddenly produced. If allowed to escape, this can be used to propel a rocket. If confined, it can explode with great force.
  • The word "jackass" is shown in this episode, when Stinky was holding up the Jackass Kicking Louisiana Hot Sauce.
  • The plot is similar to the SpongeBob SquarePants episode "Life of Crime" in that someone mistakenly thought they had committed a crime.
  • This episode is the second appearance of Sid's mom and Stinky's mom, the first being "Parents Day".
  • This is the only episode where someone foils Arnold's plan (Harold, Stinky & Sid).
  • The Furnace in the Sunset Arms basement was an "Acme" brand furnace. Acme was a fictional producer of multiple products in the "Looney Tunes" shorts.


  • Harold, Stinky, and Sid should not have been able to go near a building that was going to be blown up.

See also

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