Mike Rolph quits his job, seemingly, as a highway patrolman and takes the position of the Police Chief of W. J. Brady's oil refinery. He is also romantically involved with Brady's daughter, June. It appears that some highly-placed employee has sold out to the opposition refinery people, and much sabotage and havoc is being caused.

When Shag Smith kills Jim's brother Bob, Jim and Thunder quit the rangers so they can cross the border and join Smith's gang. Jim's plan is to get the gang to cross back over the border where the rangers will be waiting.