Mary Ann and her best friend Kolleen love a mystery, so when Mary Ann's dog sniffs out foul play at the bottom of a muddy pit, the hunt for clues is on. Their search for answers brings Mary Ann and Kolleen into contact with three girls whose parents are part of a group of migrant workers who come to Minnesota each summer to help harvest sugar beets. Little is known about the migrant workers, so Mary Ann and Kolleen's parents caution them to be on...