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What should you do if you receive a letter from yourself from the future? Believe it or reject it? Should you listen or do what you know? Takako, Azu, and Hagita also received such messages. Everything is clear, but will it work? Even they, from the future, cannot know for sure . And it insists that Kaker needs a little happiness, a little joy, a little time with his friends. So why don't they all take part in a relay race during a sports festival...

And they decide to do it.