Two teenagers Tekamei and his sister Kamei are living on Earth as normal people. Tekamei goes to school. He gets bullied and fights back like you typical highschooler. Kamei is older and works as mechanic using the house as a work shop which does get loud at times. The mother Shikamei is a mechanic as well. Their father, Ariake however works as phsycologist but thats not all he does. As it turns out he also goes to fighting arenas  in space to watch alien matches and bets on them. One of the bets he makes doesn't work out and it seems he used a suicide bomb for revenge but the circumstances are mysterious and are being investigated. To help figure it out the Control Force sends a Team Leader called Yurui, a bulky hard bodied alien to find Tekamei and Kamei and bring them into the arenas. Did their father really die or did something else happen? (Story currently uses a very different style of writing including descriptions of things like frames as this intended to be a manga but will be adapted here to be a light novel)