From the Game Manual / Box'
Tokyo Under Siege.
A Modern-Day Ninja for a 21st Century Enemy.
A parasite has mysteriously appeared, unleashing a wave of destruction - mutating humans into vicious, savage creatures. The disease has reached the shores of Japan and into the heart of Tokyo. As modern-day ninja Ken Ogawa, swing, fly, and slice your way into extreme action to save humankind from obliteration.