Rainbow Dash has a gift for Twilight. Remember when Twilight taught Rainbow Dash to love books? Rainbow dash plans on repaying the favor by getting Twilight to like a sport.
While it begins as a matter of just 'Making Rainbow Dash happy', after seeing how truly competitive the dueling club is, will Twilights competitive side come out to defend her pride?
(NOTE: Slight amount of inspiration from the Dueling Club in Harry Potter and the Chamber of Secrets, but this is not a crossover)