Watch on Soap2day. In a futuristic Tokyo where police have been privatized and bitter self-mutilation is so casual that advertising is often specially geared to the 'cutter' demographic, Ruka is on a mission to avenge her father's assassination. Ruka is a cop from a squad whose goal is to destroy homicidal mutant humans known as 'engineers', that possess the ability to transform any injury to a weapon in and of itself.