Complex sentence: Jim/Cheyenne (Rex Lease) is able to dispute the rumor and clear the stallion (Starlight) of wrong-doing, even though he is quickly fired when he is drugged and made to look drunk.
Split into simpler sentences: Jim/Cheyenne (Rex Lease) is able to dispute the rumor and clear the stallion (Starlight) of wrongdoing. However he is quickly fired when he is found drugged and made to look drunk.