Brisco is assigned to transport an English spy, Emma Steed, to Mexico as part of an exchange. Trouble arises when it turns out there is an assassin aboard the stagecoach, sent to make sure Steed doesn't get to her destination.

Pete Hutter gets hold of a Chinese baby who happens to be the future Emperor of China. He is killed by ""Chinese death stars"" (but only temporarily) and Dixie Cousins gets hold of the baby. She ends up going to Brisco and Bowler for help.