Set in the future. Humans are known as the Pure Race. And there's a second group, the Nano Race -- they have nano-machines in their DNA, and special abilities. Pure humans discriminate against the Nano people, and have control over them. 
 
Beck is a 14-year-old Nano boy. He's already a legendary bounty hunter. Beck has the power to turn into the red ash of the title. There's an expensive medical procedure for Nano-to-Pure conversion, and Beck wants it. 
 
One day, Beck and Tyger encounter a mysterious girl Call. Call pretends to be Nano but is actually Pure, and she is being pursued by a duo called Safari and Stripe. The adventure unfolds in various parallel worlds. 
 
(Source: STUDIO 4℃) 
 
Note: Part of the 2017 Anime Tamago Projects.