Over a century after the Moon's catastrophic destruction, the Earth remains unscathed, surrounded by the remnants of its former satellite. Unbeknownst to many, teenage Haruka Amami unknowingly enters the Idolmaster Project, believing it to be a typical idol audition. To her surprise, she discovers herself enrolled in a covert institution operated by the enigmatic Mondenkind Agency. Alongside other chosen girls, she is groomed to pilot iDOLs—advanced machines tasked with intercepting lunar debris. However, the agency's true motives remain murky, raising doubts about the nature of these seemingly sentient robots. As Haruka bonds with the iDOL named Imber, she experiences a stirring of emotions, prompting her to question the true essence of these mechanized beings.