Supermysteries, Passport to Danger and Copper Canyon Conspiracy were both written in 1994 and they both take Nancy Drew and the Hardy Boys over our southern border and into Mexico to solve some mysteries. This was back in the day when you only needed a driver's license to visit Mexico.
In Passport to Danger, Nancy and Bess are in San Miguel de Allende helping friends of Aunt Eloise who have an art school. The mystery is that the art school seems to be the source of fake green cards that are being circulated in the area. Nancy must find the forger. In this book, Frank and Joe are on vacation and visiting Mexico City friends who own an art gallery in that city. There is a little Bess bashing, when she is eating chips and salsa and they mention that she is always trying to lose 5 pounds. The Mexican Police tell Nancy Drew to not interfere because this is a serious police investigation and very dangerous. Nancy, Bess and Joe are held at gunpoint while the bad guy confesses all. But, Nancy, Frank and Joe all fight the bad guys and Nancy uses a judo kick to subdue him!
I was pleasantly surprised to like BOTH of these books. They had the Hardys and Nancy Drew on equal footing as detectives and they let the girls and the boys work together to solve the mysteries and fight the bad guys with neither having an obvious advantage. Romance took a back burner, although there is this quote from Passport to Danger, "somehow Bess always managed to find just the right amount of romance wherever she went." There were a lot of great descriptions of Mexico and Mexican cities! I am ready to take a trip south of the border!