Applebloom, Sweetie Belle, and Scootaloo all want to be biggest and best adventurers that Equestria has ever seen. The only problem is that everypony thinks that they are only children who aren't cable of big things. They want to prove to everypony that they can do anything and in order to do that, they accompany the Mane Six on their latest adventure to the underwater city of Bikini Bottom. It is here they meet Spongebob Squarepants and accompany him on a mission to retrieve King Neptunes stolen crown.