A freak storm destroys the Robinson's garden and condenser unit, forcing the family to ration protein pills. Dr. Smith and Will soon find a series of alien advertising signs which lead them and to an outdoor bazaar ran by a space trader. The trader shows them incredible wares - a helmet that translates languages, another that renders Doctor Smith invisible. He shows Smith tasty food from around the galaxy, but the greedy businessman's prices are too high for the Robinsons, who require every vital piece of equipment they have. The space merchant attempts to drum up business by destroying the Robinson's food supply. A desperate Smith first tries to trade Penny's tape player in exchange for food. The Space Trader refuses, since he claims not to trade with children. Still, he kindly give Penny