It hands you a whole caste system in one short sitting and refuses to slow down for you. Beck is fourteen, already a legend as a bounty hunter, and the punchline of his life is that he wants to spend that money erasing what makes him special: the nano-machines in his DNA that let him scatter into red ash. That's the ugly little truth at the center here, a kid who has internalized the Pure Race's contempt so thoroughly that his dream is to become his own oppressor. Tyger keeps him tethered, and the film knows better than to explain the world when it can just show you who kneels to whom. The animation is the reason to press play, movement that treats Beck's dissolution into ash as choreography instead of a power-up. Short, mean, and it lingers.

In a future where humanity is split in two, ordinary humans known as the Pure Race hold power over the Nano Race, people whose DNA carries nano-machines that give them special abilities, and treat them with open prejudice. Beck, a fourteen-year-old Nano boy, is already a legendary bounty hunter, able to transform into the red ash of the title. He wants a costly medical procedure that would convert him into a Pure human. Together with Tyger, a big but timid mechanic, he flies a parallel machine to the old world to take on risky jobs. One day the pair run into Call, a mysterious girl who passes herself off as Nano but is really Pure, and who is being hunted by a duo called Safari and Stripe. The three set off for a clockwork world, while Safari, Stripe and their leader Deny keep up the chase in an action fantasy adventure that spans several parallel worlds.