Some kids sculpt sand castles. Some make mud pies. Some construct great block towers. But none are better at building than Iggy Peck, who once erected a life-size replica of the Great Sphinx on his front lawn! It's too bad that few people appreciate Iggy's talent--certainly not his second-grade teacher, Miss Lila Greer. It looks as if Iggy will have to trade in his T square for a box of crayons . . . until a fateful field trip proves just how useful a mast builder can be.