One summer they plan to fly to New York for a visit. They get to the airport only ten minutes before the plane leaves. So time is short. But suddenly Mrs. Long says she must tell Linda, their daughter, not to forget to lock the front door when she leaves for school in the morning. As Linda is then at school, they can't reach her on the phone. So the couple hurries to the post office. Mrs. Long writes a short note to Linda, while Mr. Long buys a stamp and an envelope. Soon the note is ready. They put the stamp on the envelope and drop it in the letter box in a hurry. But suddenly Mrs. Long begins to cry. The short note to her daughter is still in her hand. She has put their plane tickets in the envelope!

Mr. and Mrs. Long have a poor memory, and they are also very careless. Compared with the careless parents, their daughter Linda is quite different. Linda is very careful in doing things. If Mr. and Mrs. Long can act carefully and remember to check their work, they'll not cause so much trouble in their life.