A ruthless assassin, Winston Smiles, is on the trail of Dixe Cousins because of vital evidence that she has against his employer. Brisco and Bowler come to her aid, and the trail leads to a nunnery where Dixie hid the evidence.

Juno Dawkins, another member of Bly's gang, is planning to steal an Orb for his boss. To intercept the high-speed government transport, he steals four prototype ""iron horses"" (i.e., motorcycles) from a Westerfield Club project being supervised by Socrates. To keep Socrates from getting fired and to bring in another member of Bly's gang, Brisco and Bowler go after Dawkins and his gang.