Celebrated artist Mary Jane Begin introduces fans to a brand-new land in the world of MY LITTLE PONY the underwater city of Aquastria, ruled by KING LEO. When TWILIGHT SPARKLE receives an invitation to visit the underwater world, she invites all her pony friends and SPIKE to travel with her. Together, they learn of the long-held rivalry between the seaponies and the mermares, and must navigate the oceanic world, confront danger, make new friends, and race to the finish in this adventure that takes place in a shimmering new MY LITTLEPONY world that has never been seen before!