When Sue Ellen receives a new sweater from her pen pal, Arthur teases her about it, but is unaware how much his bullying is bothering her. Mr. Ratburn tells Arthur to write an apology letter to Sue Ellen, but his letter is insincere when he tells her she overreacted. He then mistakenly sends her an insulting picture and soon realizes how much of a bully he has been. Arthur and his friends recount their best days ever.