One morning in Gravity Falls Oregon, we see Dipper Pines on the front porch of the Mystery shack reading his journal peacefully, before out came his sister Mabel carrying in her arms her beloved pet pig Waddles, walking past her brother.
"Hey Mabel where are you going?" Asks Dipper, Mabel says to him "I'm taking Waddles to the vet today for a checkup wish us luck" waving to her brother.
As Mabel leaves, she tells Dipper "make sure to let Grunkle stan I'll late for lunch alright?" Only for Dipper to respond "yeah yeah good luck Mabel."
Later that afternoon at the Mystery Shack ,we see Dipper and Stan having egg salad sandwiches for lunch, as rain poured outside while the two ate in silence.
Stan looking around the room afterwards, asks "hey kid where's Mabel?" Dipper simply replies nonchalantly "oh she's taking Waddles to the vet today, she wanted to let you know that she's gonna be late for lunch today."
"Its always something with that stupid pig of hers ,honastly what does Mabel even see in that thing?" Asks Stan annoyed out of his mind.
Dipper looking at the wall clock notices that his twin sister still hasn't returned, asking himself curiously "hey what the heck is taking her so long to get back anyhow?"
Afterwards, we see the front door slammed open by a soaking wet Mabel ,with a frightened look on her face holding her beloved Pig in her arms ,walking to the couch in the living room before she plants her body on it.
When the two saw her, Stan begins to scold her saying "hey Mabel, what where you raised in a barn? Close the door behind you next time you come in will ya?" Although Mabel does not respond.
After closing the door, Stan then notices the trail of water she left behind and rants "and you didn't even wipe your feet ,someone's going to have to clean that up and it sure as heck won't be me!" Says Stan ,before he finally notices to look on Mabels face.
"Uh hey Mabel, what happened what did the vet say?" Asks Dipper concernedly, only for Mabel to suddenly break down loudly crying abruptly ,while holding Waddles in her arms.
Dipper tried to calm her down afterwards ,saying "whoa whoa Mabel calm down, whats wrong? Did I say something wrong, whats wrong?"
All Mabel did next was calm down from her crying ,as she proceeds to look back at her family "oh Dipper ,Grunkle Stan it-it was awful just awful" she sobs.
"Whats wrong Mabel, what is it?" Asks Dipper as Mabel in a cracked voice, answers " t-t-today at the -at the vet ,t-they said that h-he won't last, and-and thats because Waddles only has...EIGHT DAYS TO LIVE!" Crying even more loudly then ever ,after telling her family this.
Grunkle Stan annoyed by what Mabel had said, begins to rant saying "seriously kid ,all this drama is for some stupid pig thats gonna die?" To which makes Mabel cry more.
Dipper not wanting to see his pig loving sister cry anymore ,he places a hand on her back and makes an attempt to calm her down.
"Look kid if the pig means that much to you, why don't we get you another one after the pig croaks ,what do you say?" Asks Stan.
Unfortunately Mabel doesn't take too kindly to the idea as she sobs "b-but I don't want another pig, I WANT WADDLES!"
As Mabel continued to cry ,Dipper tries to think of a way to cheer her up.
Then as if struck by lightning, something hit him before turning back to his sister asking "hey Mabel ,you said that Waddles only has eight days to live right?"
While sobbing onto Waddles ,the only answer she gave was "uh huh." All while her eyes and nose continue to run much to his disgust, before Dipper suggests to her "well you know you don't have to spend that time crying about it" causing Mabel to wipe away the tears from her eyes ,asking "I don't?"
Dipper then explains to her "of course ,instead of crying about it we can try giving Waddles here the best eight days of his life, you know make it worth his while, and I'm going to be the guy to make it happen."
"Would you Dipper?" Mabel asks curiously, in which Dipper with an assuring nod replies " I promise" Mabel then hugs him, continually thanking him.
Stan as he attempts to leave saying "well looks like you two have allot of work to do ,so I'll just leave you to it." Only for Dipper to stop him, saying "hold it Grrunkle Stan! You're gonna need to help out too!"
"WHAT!" Stan asks in complete shock, as Dipper explains "Waddles means allot to Mabel, and in order to make her eight days with Waddles the best ones, I think its fair that they're best remembered with the family the little guy had come to love."
Mabel letting go of her twin from the hug, then says "Awe thanks Dipper." Dipper, as he escorts his sister into the kitchen ,simply comments "Mabel starting tomorrow, the following days will be spent only for Waddles.