Her long career included field research and in museums such as Transvaal Museum (now the Ditsong: National Museum of Natural History) and for the University of Pretoria on southern African mammals, starting with the animals from Iron Age sites at the Kruger National Park.
Her work resulted in her publishing 130 scientific papers mostly on the skeletal remains of animals.
She also published a book titled What Bone Is That? A Guide to the Identification of Southern African Mammal Bones.During her research work Plug traveled widely to many countries to enhance her knowledge base and participated in many meetings of the International Council of Archaeozoologists (ICAZ) of which she is now a Council member.