|"Sue Ellen's Lost Diary"|
|Number in season:||14A|
|Original Airdate:|| April 9, 1998|
|Written by:||Peter K. Hirsch|
|Storyboard by:||Ivan Tankushev|
"Arthur the Unfunny"
While helping Sue Ellen look for her missing journal, her friends start to wonder what exactly is in it.
One day when Sue Ellen is walking through the library, her diary fell out of her hands. Sue Ellen realizes it and searches for it. Then she sees Francine and scolds her, but when she picked up the book, it was just a joke book. Francine feels suspicious. Later at Muffy's mansion, Francine discusses the diary incident with her, who says Sue Ellen might write something about her which made Francine more suspicious. Back at the library, Muffy offers to help Sue Ellen look for her diary. Then Muffy runs into Binky, who claims he didn't read Sue Ellen's diary. Binky runs off to find it, only to bump into Arthur. As Arthur tries to get his books, he finds Sue Ellen's diary, which he reports to his friends. As Arthur and his friends look at the diary, they were trying to choose whether to read it or not. Meanwhile, Sue Ellen was explaining about her diary when Arthur and his friends show up and gave her the diary. Later, as Arthur and Sue Ellen are heading home they pass by Arthur's house where he reassures her diary is still private. Relieved Sue Ellen told Arthur that he would have been embarrassed as she said some pretty nice things about him making him blush then heads home herself.
- Sue Ellen's comment at the end, "I said some pretty nice things about you!", is a reference to Arthur's original crush on her in the books.
- During Muffy's fantasy, she plays as Princess Millicenta who wears a blue princess dress and long curly hair. After the dragon comes into the castle, Millicenta began to wear her blue princess hat. After the knight is stuck in the castle door, Millicent's hat is gone. When Millicenta comes out of her castle, she wears a single braid, but still wearing a princess dress. However, in Arthur's New Friend and Arthur's Perfect Christmas, Muffy stills wears a princess dress and a princess hat, but double braids just like in her original appearance.
- At the end of the episode Sue Ellen and Arthur were outside talking but when Arthur blushes after Sue Ellen leaves on her bike, he is suddenly inside the libary.