A typical high schooler's life takes a peculiar turn when he encounters a powerful and clever mechanical arm named 'Mecha-ude'. This unexpected meeting leads to the arm residing in the boy's hoodie, sparking a series of adventurous and challenging moments for the duo. As they battle together and forge a strong bond, they befriend others who possess their own unique 'Mecha-ude' partners. Among them is a spirited heroine with two 'Mecha-ude' emerging from her skirt, captivating the hero with her contrasting personality. However, their camaraderie is tested by rival 'Mecha-ude' users seeking the arm's enigmatic secret. In this tale, sentient anima-machines like 'Mecha-ude' emerge, displaying emotions despite their mechanical appearance. They experience a range of feelings, from anger to sadness, fueling their determination to combat foes.