Rikka is a ninja descendant. Her grandfather Hyoe is the last chief of their ninja clan and her father is a cyborg researcher. Both are killed when a weapons' company raids his lab to use his research. Rikka sets out to avenge their deaths.
Moshimo, Japan. The annual fireworks festival is about to take place and a group of schoolboys, arguing over whether they are round or flat when viewed from different angles, set out to find it out.
