The Mystery of the Targeted Merchants

is episode 188 of the original Naruto anime.

Synopsis
After an attack by Ruiga, one of the three Criminal Brothers results in the death of Kikunojō and Naruto notices that their attackers are looking for a specific person, Naruto's group realises that they have not been told the truth about the peddlers. They learn that the peddlers were being used as cover for the Land of Vegetables' princess Haruna in order to escape from the Three Criminal Brothers. It is then revealed that she does not trust others and is willing to sacrifice other people to protect herself, believing that it doesn't matter who dies as long as she, the only one who can rebuild her country, survives.