While hastily attempting to rescue her father and the dying world of Eltria, Kyrie Florian is betrayed by her childhood companion Iris. Moreover, the strength Kyrie has amassed from Nanoha Takamachi and the other Earth guardians cannot be employed to aid her father. Iris dismisses the distraught Kyrie, having secured what she sought to retaliate against Yuri Eberwein, a formidable entity that remains dormant on Earth. With the wreckage left behind, Nanoha and her cohort must face the vexing Iris to reveal the truth and halt the clash between her and Yuri. Yet amid the fierce conflicts, a far more perilous menace skulks in darkness and threatens all who oppose it. Regardless of any hurdle, Nanoha stays steadfast and readily uses her magic to assist those who need it.