Pingu comes in from playing with his ball and sees a letter on the table. The letter is sealed, and has nothing written on the envelope. He wonders what it might be about but leaves it and has a snack. He is about to go out again when curiosity gets the better of him, so he returns to the letter, opens it and is about to look at the contents when he hears someone coming. He quickly hides the letter, just before Pinga and Mother enter. Mother notices the letter is no longer on the table, and asks Pingu if he knows where it is. Pingu says he doesn’t, so Mother and Pinga search everywhere for it. Mother then asks Pingu again if he knows about it, and this time he owns up to having opened it and gives it to Mother. It was for Pingu all along, and is an invitation to a party. Pinga shows Pingu her own invitation that she’d already opened. Pingu then notices that the party is today, and it’s now the time that it’s almost time to start, so they have to rush to get there, and they make it just in time before it started.