Arthur Season 2 Episode 10 D.W. Goes to Washington / Arthur's Mystery Envelope >Mr. Haney, the principal, gives an envelope to Arthur to give to his mother. Arthur is worried about the contents of the envelope, thinking that he is in big trouble, so he tries to hide it from her. D.W. insists on showing the envelope, so she can see how much Arthur is going to get into trouble. When Arthur finally reveals the envelope, it turns out to be Mr. Haney's tax returns, as Arthur's mother is his accountant.