Lincoln finds a quarter between the couch cushions, but his sisters (minus Lily) discovered this soon after and, since money is hard to come by in the Loud house, they get in a fight over it. Mr. Loud stops the fight, and makes the kids clean the attic as punishment for their greed and roughhousing for money. While cleaning the attic, Lincoln discovers a letter supposedly written by the house's previous owner, Sharon DeMonet, saying that her family always fought over money and that she has hidden a stash of money on the property. When Lincoln tells his sisters of the letter, though, they pretend not to believe it, only to begin searching the house to find it. When Lincoln catches them in the act, they brawl once more, and Mr. Loud tells them to stop fighting, and finish cleaning the attic.
Back in the attic, Lincoln re-reads the letter and, by looking in a mirror, finds a second letter from Sharon DeMonet in the reflection. He reads this next letter, which says that they must "get to the bottom of the matter" to find the next clue. This causes him and his sisters to rampage through the house, searching every nook and cranny to get the money (though they make sure to keep quiet when they search Lily and Lisa's room because Lily is napping). After another struggle results in them ripping the letter into nine pieces, Lincoln tells his sisters that if they just keep fighting, they won't be any closer to finding the money. Realizing that their brother is right, the sisters decide to settle their bickering, and promise to work together from now on. Lily then walks in on them, having woken up from her nap, and they find an envelope taped to her diaper. Inside is a map that tells them where the treasure is hidden.
The siblings follow the map, which leads to a big, red "X" in the backyard. Lincoln and Lucy dig it up as they get extra help of Lana. They find a suitcase containing $500, which they split evenly, for all eleven of them, meaning that they each get $45.45. Back inside the house, the Loud parents watch their kids celebrate their outside, revealing to the viewers that Mr. Loud invented the whole "Sharon DeMonet" charade to teach his kids to work together and share, and that the money they found was his work bonus. But since his plan ended up causing so much damage around the house, Mrs. Loud forces him to clean everything up.
- This episode's title is a reference to the movie It's a Mad, Mad, Mad, Mad World.
Home video releases
- The Loud House: Welcome to the Loud House - Season 1, Volume 1