Under the city of Tokyo is a world called the Underground populated by Elemental Users who can manipulate the elements. When Ruri Sarasa and her boyguard Chelsea Rorec escape to the surface they take refuge in Rumina's home. When a battle occurs Rumina is thrown into the battle and discovers that he now has the power to manipulate air. Befriending for Ruri, Rumina has decided to do whatever it takes to protect her even if it means going into the Underground.