When The Cutie Mark Crusaders go missing, Applejack, Rarity, and Rainbow Dash must sail into the ocean to find their beloved family members. What they find instead is an underwater city built by a mad genius as a utopia where Equestrian law does not apply. Unfortunately, this utopia quickly turned into a nightmare, and now the city of Rapture is a minefeild of zombie-like drug addicts and genetically altered psychopaths.

The three ponies have no choice. They are willing to go through the depths of hell and the ocean for love, and that is exactly what Rapture intends to do with them. But are the girls making the right choice? Do they even want to see what their sisters have been made into? And are they ready to unravel a mystery older than themselves? Only time will tell, and unfortunately for the Cutie Mark Crusaders, that time is running out.

Important! Comes before Crusaders of the lost Mark.

Story rated Mature for Blood, Gore, and Strong Language.