The Ninja is set in Japan's edo era, circa 1630, where Gyokuro, an evil emperor, has gained power and is oppressing the people. The princess who opposes him is confined to a dungeon within the Ohkami castle, guarded by the ninja clan under Gyokuro's control.
You play as Kazamuru, a great warrior who challenges the clan to a fight to rescue the princess. To do so, he must find the five scrolls in the thirteen areas of Ohkami. Along the way, you'll face various ninjas, including Kuno-ichi and Ninniku, as well as fire-blowing, slashing, and footloose ninjas.
The gameplay involves exploration, platforming, and combat. You'll navigate through grassy fields, shrines, river banks, towns, and the castle itself, with some steps requiring unique solutions. For example, you must avoid boulders in certain areas, use logs to cross rivers, and scale cliffs.