The now full-grown grandson of the mighty Stallion is ready to go and write his own legend. With his trusty friend Leo by his side, the adventurers encounter a friendly gang of cowboys, a group of foreign smugglers, and a band of horses led by the fierce Bandit, who is also the captor of Stallion's former foe: Thunder. Lightning must face this dangerous new challenger to get Thunder home, but when Bandit comes back from defeat for revenge, he's got a big surprise, and Lightning, Comet, Leo, Rugby, Rodrigo, Stallion and an old friend must fend these enemies off once and for all. Can Lightning prove he's worthy as the next herd leader?