Malcolm's family and scores of others are forced to relocate to a school gym because of a toxic-chemical spill caused by a derailed train. Seems it ran over an old couch that fell off Hal's car on his way to the dump. Amid the chaos, resourcefulness pays off for Dewey, who enlists sympathy by pretending his parents were killed in an enveloping chemical cloud; and for Reese, who schemes to make money off the calamity. As the rascal puts it, "When people are miserable and suffering, it brings out the best in me."