1x109 - Heathcliff and the Catillac Cats

It's Heathcliff's birthday, and he's a very happy cat. That is, until he realizes all his friends have forgotten! Everywhere he goes, cats and people blithely tell him they're busy, and send him away. Angry and hurt, Heathcliff decides to run away. When he goes into the Nutmeg home to get his things, everyone is there yelling, "SURPRISE!"