Chad and Joe are planning to spend the weekend at the festival in San Gill but Captain Parmalee is leaving down to make a speech and puts them in charge of the office. Reese returns from a mission so Chad and Joe con him into being acting Captain but he immediately assigns them as stand-by for the weekend. Chad then alters a telegram to say a prison escapee is headed to San Gill so Reese sends them out to track him down. Once they arrive they discover that San Gill is where Parmalee is giving his speech and they immediately buy masks and serapes to disguise themselves. Reese eventually learns the outlaw was killed escaping and heads to San Gill after Chad and Joe. The three Rangers stumble onto an assassination plot that includes 6 Mexican government officials with Parmalee thrown in for good measure. They foil the attempt with fireworks and leave San Gill without being seen but having been heard by Parmalee. The Captain returns to Laredo and assigns them to seek out three Lared

Prince Lazlo of Ambrasia is fascinated with the Texas Rangers and picks Laredo as the site to sign a treaty with Aguacaldo. His half sister Helena and consort Karl see this as their perfect opportunity to kill Lazlo, which they attempt with poison and a hired gun. Chad Cooper is a dead ringer for the Prince and Captain Parmalee decides they should switch identities for the Prince's safety. Reese believes the Prince to be Chad dressed up until the Prince passes out from drinking a shot of red-eye. The ruse is eventually figured out by Helena and Karl whose hired gunman goads the Price dressed as Chad into a gunfight. Chad is able to substitute for the Prince at the last moment and scares the gunman off with his fancy gun-handling. The gunman kidnaps the Prince and demands more money from Helena. Reese and Joe rescue the Prince and return him in time to sign the treaty and expose Helena and Karl.