From Viz:
Decades ago, a being known as the Giant of Light joined together with Shin Hayata of the Science Special Search Party to save Earth from an invasion of terrifying monsters called Kaiju. Now, many years later, those dark days are fading into memory, and the world is at peace. But in the shadows, a new threat is growing, a danger that can only be faced by a new kind of hero. A new kind of Ultraman.
Shinjiro is an ordinary teenager, but his father is the legendary Shin Hayata. When he learns that his father passed on the “Ultraman Factor” to him and that he possesses incredible powers, nothing will ever be the same again.