With the formation of the Specialized Extracurricular Execution Squad (S.E.E.S.), Minato, Mitsuru, Akihiko, and the rest have taken it upon themselves to combat the threat that Tartarus and the Shadows therein represent.

When they learn that the soft-spoken Fuuka may have become trapped in Tartarus during the Dark Hour, they mount a desperate rescue attempt – but will they reach Fuuka in time to save her?