Carbou 1, a Charcadet raised alongside another Carbou, bubbles with mischief and a thirst for adventure. After a battle defeat by the human trainer Yūto, Carbou 1 chooses to leave its lifelong companion behind, joining Yūto on a quest for strength. This decision marks the start of their separation, leaving the other Carbou alone.

Under Yūto's guidance, Carbou 1 undergoes intense training and battles, evolving into Armarouge. Its journey focuses on growth forged through conflict and the relentless pursuit of power, a stark contrast to the quieter life of its childhood companion. The narrative traces their divergent paths, exploring whether the two Carbou might eventually reunite. At its heart, Carbou 1's story grapples with ambition, sacrifice, and the enduring bond between them, unfolding as a passionate yet bittersweet journey.