What Will Happen If...? is the thirteenth episode of Season 1. It's a 2-part special. Note: This episode is divided in subplots, much shorter than a regular episode due time.
Part I: Let's Make Some Changes
5 of the Loud siblings tell how it will be the life if had some changes.
All starts with Lincoln near the fireplace, he tells the viewer all the 'common' things that happen in his diary life. Suddenly the sisters appear, believing he's going to tell a story. He tells the sisters the truth
Lincoln tells his change first. He saiys that if he can change a thing, it will be the number of sisters. He tells different truths, starting with one sister. He tells that it will be great having less sisters, but he feels that is not enough. Later there are two sisters, but isn't enough, later with three, but still not complete, later with four, the circle is almost complete, but Lincoln doesn't like to have a big room with too many space and few things. The subplot ends with him enjoying of his 5 older sisters.
The Leni's change focuses on her being smart. All starts when she drinks an experimental formula that makes people smart, but when she becames smarter than Lisa, this last becomes jealous of her. But Leni is gone to Harvard to study laws (duh). This makes Lisa to go on a small depression, but she remembers that the science doesn't have emotions, so starts to work in an antidote.
Lana tells her siblings, that its ideal change, will be that Lola being less 'femenine'. All starts when Lana is playing on the mud like usual, only to be surprised by Lola, by for some reason, wants to play in the mud too. So the twins start to make a mud war. Later the other siblings join to the fun.
Luan has a small change to the family, making her jokes being really fun. One morning, she is telling a joke routine, when all laugh with her jokes. Later she goes to a b-day party and all her baddest jokes, are funny to the kids.
Lynn's change includes Lincoln to be more sporty. All starts at the football camp from the Loudest Yard. But instead of her taking his place, Lincoln is playing by his count. Later Lincoln agrees to play badminton, basketball, baseball (and other sports that end with -ball).