Subaru's quiet life shatters when mysterious creatures called UMAs begin possessing humans across the world. These beings are fragments of Mu, an ancient civilization lost to time, and they're hunting for powerful artifacts known as ooparts to resurrect their sunken homeland. Each oopart Subaru recovers grants Rockman the ability to transform into a new warrior form, pushing his power beyond anything he's encountered before. Guided by the brilliant Professor Orihime, Subaru and his partner War-Rock race to locate the ooparts before the UMAs complete their ritual. What starts as a straightforward treasure hunt becomes something far more complex when Subaru realizes the stakes extend beyond stopping a revival: the UMAs' desperation hints at something deeper, a truth about Mu that changes everything. Rockman's transformations, from Thunder Berserk to Fire Dinosaur, make every battle feel fresh and urgent. The series balances high-energy action with genuine mystery, keeping you guessing whether the UMAs are truly villains or something caught between two worlds.