Metroid: Diffusion is a fanon Metroid game for the Nintendo DS. Unlike Metroid Prime Hunters, Diffusion is a 2-D Side-Scroller. The game takes place between Metroid Prime 3 and Metroid II. Chapters 1-4 take place on SR388, chapters 5-12 take place on Norion and then the last chapters, which are 13-15 take place on Tallon IV. The game is about a galactic Space Pirate Invasion. A small part of Chapter 7 takes place on the Pirate Mothership. After chapters 4, 12 and 15, Samus returns to the GFS Olympus for her next mission briefing.