Well obviously like every other monkey ball, there is a regular main game mode where they do the usual monkey balling through levels, but as for the story itself its a bit hard to tell at the moment. I can see it going the Banana Blitz direction where there's one cutscene at the beginning explaining the main goal of the story (likely something along the lines of Jet stealing some sort of important monkey artfact/Banana) and then one at the end showing them completing their goal.
Though if you can find someone who can translate the japanese on the official website you could probably get a proper image of what the game'll be like.
Originally Posted by 0LunarShadow
Who cares about challenges?! We can totally take on anything 'cause together we're the SEGA FORUMS!!!