Batman, along with many of his allies and adversaries, finds himself transported to feudal Japan by Gorilla Grodd's time displacement machine.
On August 16, midway through a seemingly endless summer vacation, middle school third-year student Nagara, transfer student Nozomi, classmates Mizuho, Asakaze and their entire class are suddenly transported from their tranquil lives to a school adrift in an alternate dimension. They must survive with the super powers that have awakened within them.
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.
