At home in Mario Brothers Plumbing, Mario and Luigi are watching a wrestling match on television to see who wins, and at first fail to notice a young boy with a suitcase walking down the steps into the basement. Turning his head, Luigi identifies the boy as Brian Bonsall, and questions as to why he's carrying a suitcase. Brian claims that he's selling pots and pans door-to-door, but Mario and Luigi don't buy his story. Brian then tries to convince them that he's instead selling encyclopedias, and then tupperware, but the brothers don't fall for his lies, although Mario is tempted by the tupperware. Realizing that he can't hide the truth, Brian reveals that he's running away from home.
Mario asks Brian why he's running away from home, and he explains that his parents don't love him anymore. Brian figures that he can teach his parents a lesson by making them miss him while he's gone. Luigi suggests that they should talk about this situation a bit, and Mario nods in agreement.
Sitting down at the table to some pizza, Mario tells Brian that he doesn't want to run away, but Brian merely thanks him and Luigi for the pizza, stating that he doesn't want to run away on an empty stomach. Mario explains to Brian that he shouldn't want to run away, no matter how bad things may seem at home. However, Brian states that he's made up his mind and wants his parents to learn to appreciate him. Mario then tells Brian that when he and Luigi were kids, he ran away from home, and begins to explain his story through a flashback.
As kids, Mario and Luigi are shown to be living in the same basement where Mario Brothers Plumbing is located in present day. Rushing in through the back door, Mario runs over to some toys, excited that he just beat Luigi in a little race. Luigi then bickers with Mario, until Mama Mario shows up, telling her sons not to fight. Mama then tells Mario that since he's the oldest he should know better, and grounds him, much to Luigi's delight. Mario complains that he's already been grounded five times this week, so Mama instead tells him to peel garlic for the next five days.
Mario whines about not wanting to peel any garlic and complains to Luigi that since he's always getting him in trouble, that he'll run away. Grabbing a stuffed dog and a baseball mitt, Mario runs off, with Luigi unconcerned about his brother's welfare, and the flashback ends.
Brian then tells Mario that he must've had fun being on his own, and Mario assures him that such a thing wasn't the case. Mario explains that back at home, his family's hearts were breaking. Luigi then sarcastically tells Mario that they were miserable without him, and another flashback starts up.
At home with Mama, Luigi helps himself to some popcorn, and is thrilled to not have to share it, or the couch with Mario. Luigi praises Mama, and she explains that without Mario around, there's more of everything for them. Just then, Mario returns home and apologizes for running away. However, Mama doesn't appear to be very grateful. Mario asks if she missed him, and she replies that she doesn't miss his yelling, his fighting with Luigi, or his messy room. However, she admits that she did miss Mario, and smacks him with her purse. Mario questions why, and she tells him that it was just in case.
After the flashback ends, Mario comments that he can remember the events as if they happened the previous day. Brian tells him that the story was so beautiful, he's ready to barf. Mario asks Brian if he's learned a lesson or not, and Brian claims that he shouldn't run away since his parents will enjoy his absence too much. Mario agrees, and Brian decides to head home before all the popcorn is gone. As Brian leaves, Mario and Luigi bid him farewell. Luigi then begins to chuckle about how he and Mama "missed" Mario when he ran away.
Names in other languages