It all started with a friendly debate. Twilight thinks that Ponyville could not survive for thirty days without adults, Discord thinks that it could. Discord decides to settle the answer once and for all by putting every school aged colt and filly in Ponyville (plus Spike) into an exact replica of their town without any adults at all.
Only, Discord has to be able to prove to Twilight who won their debate. In order to keep Ponyville adult-free, he pulls filly Twilight from the past, who has nothing more than filly memories. And, while he's at it, he may as well bring in the rest of the filly mane six. Can the town survive for thirty whole days? And will the mane six be able to overcome the social barriers between themselves and the rest of the colts and fillies?