Every summer America experiences a foreign invasion. Thousands of people - mostly participants in international student programs - come to the country to work. For several months, supermarkets, amusement parks, children's camps, construction sites and restaurants fill their staff with foreign students. There is so much work in the United States today that neither the local population nor the immigrants can handle it. Therefore, American entrepreneurs, in an effort to reduce costs, are sending foreigners, including students, from overseas. They are usually offered unskilled jobs with low wages, which an American is unlikely to take. And visitors, as happens in all developed countries, do simple work that does not require serious skills: washing dishes, building and repairing houses, cleaning parks, fastening seat belts on daredevils who decide to ride a roller coaster, or accepting an order with a smile at McDonald's: "A dollar and fifty cents is your change, sir"...