Demeter is daughter of Gaia (Mother Earth); she is sister of Zeus (Electricity and Universal Energy); and she is mother of Persephone (Queen of the Underworld that is the Material Body.)
Persephone is promised by Zeus (Universal Energy) to Hades(Ruler of Death) and without Demeter's permission is kidnapped and brought underground. Demeter falls into a deep depression causing all Life on earth to wither and begin to die. Zeus sees he needs to rectify the situation and sends Hermes under ground to get Persephone and bring her back. Unfortunately, she'd eaten seeds of a pomegranate which only permitted Persephone to return for a portion of the year. Her descent into the Underworld (the material body) and ascent annually (to Life) are a symbolic way to describe the yearly agrarian cycle. I imagine that farmers were able to retain an oral calendar using these myths to know when to start planting seeds, when to harvest, when to let fields lay fallow, etc.
We find our oldest maternal ancestors in this story. We find the Soil of Earth, our Grandmother Gaia. We find Universal Life Consciousness, our Mother Demeter. And, we find the myriad Food Plants that sustain us bodily and spiritually, our daughter Persephone. We can conceptually read this story and only get a mental symbolic picture of these parallels or we can literally touch our feet to the ground and feel we are connecting with our Grandmother, the earth. We can feel the Life beat in our chest and be in conversation with our universal Mother. We can look at the food on our plate and understand how it is our nurturing and care that brings our Daughter back to us year after year.