DISCORD has finally made their move against Equestria, and has made their intentions known. They have stolen a super weapon called the Sword of Starswirl, and if Equestria does not surrender to DISCORD, then they will destroy not just Equestria, but the entire world. However, Joe discovers a clue at a local health spa, and that clue leads him to the underwater realm of Aquastria, home to the Seaponies and Mermares, ruled by King Leo. However, there is something sinister about the underwater king, and the Mermares are becoming more aggressive against the Seaponies. Joe will have to work fast to find the weapon, but the only pony who may have a clue to its whereabout is King Leo's mistress; a fun-loving mare named Lyra Heartstrings.