ALWAYS STAY BY YOUR SIDE

This is about Hideyoshi Takeuchi, works as a civil officer in the Kobashigawa Security Agency and Matsuno Keon a researcher in the Matsuno Research Group that was led by her parents.
This research group studies the new found energy source called the Takatsugu Energy Crystal found in Kyoto Japan. It was named after the former Lord of the modern ninjas, Takahiden Takatsugu, he was the first to find and use the crystal. The crystal was the most powerful magic crystal in the world, once you use it you will become immortal but if you overused it you will be banished in this world.
The modern ninjas were called the IGA Ninjas, and use the I.G.A. Incorporation as its disguise. The IGA ninjas have been the number one enemy of the Kobashigawa Security Agency and have been interrupting the Matsuno Research Group's work.