Pinkie Pie has just returned home, and is ready to get some sleep. It's 3 AM, after all, and she has a huge party in the morning. It's Rainbow Dash's birthday! And tonight is just like every other night... which is the worst part. Pinkie is fighting a battle no one else knows about, and she doesn't know if she can ever win. And the enemy is one she's never been able to escape...

Herself.

This episode takes place the night before Pinkie Pride, when she meets Cheese Sandwich.