Callie and Fen love visiting Grandpa on the farm, but this time he shows them something they've never seen before: a solar farm. He teaches them about the soil on his farm and how farmers for centuries have cared for it in order to feed the world - and how the strange "farms" filled with blue glass and posts may damage not only the soil they rest on, but poison the soil and water for miles around. Grandpa's calm, sad voice educates even adults...