Wagstaff City’s Go Green Go-Cart Race is one week away, and Martha (the talking dog) and Helen decide to build a solar-powered go-cart. T. D. and Alice build a wind-powered go-cart, and it looks like Ronald and Reginald’s is powered by goldfish—is that even possible? Based on the PBS series Martha Speaks, this 24-page early reader with full-color illustrations is a lighthearted introduction to alternative energy and environmental terms. A natural for Earth Day!