While escorting a flock to Pecos, Luke is arrested by pseudo-judge Roy Bean, aided by his bear Joe.

He gives everyone fines for stupid reasons (for example, he sentenced a Mexican named Jacinto to a month of forced labor simply because he had shaded him by the way).

However, Bad Ticket is even worse than Roy Bean and decides to hang Lucky Luke who only escapes with the help of Joe the bear.

The prisoners manage nevertheless to escape, not without flooding the cellar where they were locked by digging a tunnel which lets in the water of the river.

Some citizens, including Jacinto, see Luke and Roy Bean covered in flour, and take them for ghosts.

Roy Bean judges Bad Ticket and the undertaker and condemns them to leave Langtry and never return.