Curious George has his heart set on a red train engine at the toy store only to find he did not have enough money.  Although he does not know how long it will take to earn it, he is determined to do odd jobs and save money.  He learns about addition and hard work along the way.  Finally able to buy the engine, he sees children trying to get a windsock out of a tree.  George sets his piggy bank on a bench and helps retrieve the windsock.  He forgets all about his bank as they all play together the rest of the afternoon.  When he returns to the bench, the bank is gone.  As he sadly walks home, he passes the toy store and sees a little girl holding his bank.  He rushes inside and discovers she and her mother saw it in the park and were returning it to the store whose label was on the bottom.  As George hurries over to get “his” engine, he realizes he should thank the girl and reward her for her honesty.  He buys a less expensive train for himself and another for his new friend and fellow train-lover.  Money facts are included in the back.  Illustration style is reminiscent of other books by Margret and H. A. Rey.