D, a monster, and Hibiki Sakurama, a Ranger, have found a mutual goal in ending the war…one way or another! Hibiki is determined to reform the Ranger Force from the outside, and D vows to crush it from the inside. To that end, he has once again infiltrated the Ranger Force by swapping places with Hibiki, but the real hardship is only beginning. If he wants a shot at the Dragon Keepers, D must first pass the Ranger training to move up the ranks. Yet, with the sudden visit of Hibiki's sister and the discovery of a mysterious monster hiding in his closet, how will D manage to keep his identity hidden? In the heart of the Ranger Force, discovery will mean certain death!