If you haven’t known about the overall story in the game, check it out via gematsu:
The story in Inazuma Eleven Ares will take place right after the series’ first title, Inazuma Eleven, and the story will be developed as a parallel world story. Although all 11 members of Raimon Middle School football team are new characters, some popular characters from previous series will also appear. There will be three protagonists, and the story will be developed from three different points of views — there will be a new system known as a ‘sponsorship’ system, where corporate entities are entitled to become official sponsors of the football teams.
Can’t get enough with only the outline of the story and a screenshot? Enjoy the trailer then: