Grab the reins with Seymour & Hau as they help their new pals Rosanna and Massimo, who are saddled with a big problem! Tradition comes first in Siena during their huge horse race called the Palio. The town is jam-packed with people singing, waving flags and cheering for their neighborhood horse to win the race. But, what if a little sting turns into big trouble and a GIANT secret? Will their spur of the moment decision have enough horsepower to save the day, or will their idea run them into a huge mess?