On a rainy summer day Findus asks Pettson to tell him a story. He wants to hear the one about the time he disappeared - even though he’s heard it many times before. After a little persuasion Pettson agrees, and begins to recount the story of how Findus came to live with Pettson, and how he almost lost him again. The story begins when Pettson lived all alone on his farm.

Pettson has planned a quiet, relaxing day of fishing with Findus. As they arrive at the Lake, Signhild pulls up in her van. She starts setting up for a fishing contest and assumes that Pettson is there to sign up. Pettson has no intention of doing this. When Findus sees that there’s a delicious prize for the winner he pleads with Pettson to take part, but Pettson is determined to have a quiet day.

Pettson and Findus are having fun skimming stones across the lake, until Pettson takes a tumble and falls into the water. He splashes around till he finds his footing, but Findus is not very impressed with his swimming skills. Pettson tells him he is a very good swimmer and was given a ‘guppy badge’ when he was young, by the famous swimmer Arne Borg, so this proves he can swim.

One day Pettson’s potato patch comes under attack from some rare demoiselle cranes. This invasion attracts the attention of another unwanted visitor, Hillevi the bird watching enthusiast. Pettson is not keen on having his potato patch ruined by the birds, or on having any of Hillevi’s bird watching friends trample over his farm. He decides that something must be done.

Sometimes life is hard for little cats, at least Findus thinks so. It seems to him that big old men get to do lots of fun things that little cats can’t do. Just as he is drifting off to sleep he sees a shooting star and makes a wish. In the morning something seems different when Findus wakes up.

Pettson and Findus are cleaning out the attic looking for old things they can give Henrik for the flea market. Findus comes across a wonderful ‘ship-in-a-bottle’ that he definitely wants to keep. Henrik arrives to take away Pettson’s unwanted items and in the rush of getting everything ready Pettson accidentally puts the ‘ship-in-a-bottle’ in the box to give Henrik.

Pettson is enjoying a relaxing morning listening to music in his garden. Findus wants to play with him as he’s had enough of playing with the hens, but Pettson isn’t interested today. He’s going to have a lovely quiet day for once - or so he thinks. Out of nowhere a large object comes crashing into the garden.

Youngsters Sune and Josefina meet Findus and tell him about Father Christmas. Very excited, Findus runs back to Pettson who is in the middle of inventing a new machine. Findus tells Pettson that Santa Claus is supposed to come soon, but old Pettson is not really listening. Findus explains to the old man that they must write a wish list to Santa Claus.

The next morning Findus hurries to his snow lantern. The candle inside has melted the snow and his wish list is gone. Findus follows the footsteps he sees in the snow up into the woods, whereupon he meets a strange postman who has got himself entangled in a tree by his beard. Findus frees the postman, who thanks him and in return teaches him the most delicious language to him: They speak sausage!

As Singhild arrives on her motorcycle sledge, neighbour Gustavsson drops a pile wood in front of Pettson’s house. Gustavsson has told Singhild that Pettson is willing to carve 100 wooden Santa Claus’ for the Christmas bazaar. Singhild thanks Pettson for his generous offer, which he doesn’t dare back out of. In return he asks Gustavsson whether he could dress as Santa Claus.

Findus is angry because Pettson has no time for him at all. Findus invents a coffee pot that automatically serves Singhild coffee. But no one really notices his invention. Singhild wants to know how far Pettson has got with the carved wooden Santa Claus’ but Pettson is only thinking about his Santa Claus machine. When the Mucklas steal a screw nut off of his machine, Pettson is enraged.

Pettson and Findus go out into the woods to find a Christmas tree. Findus shows Pettson the place where he met the strange postman. Now he remembers the package that he had until now completely forgotten! The two wander through the woods, and hear someone playing the violin sadly and call out for help.

Prillan and her hens are really annoyed. Pettson makes a lot of noise when he hammers away in his barn working on his invention. The hens don’t get any sleep anymore. Pettson jumps for joy and storms out of his shed. It finally works!!! But then his Santa Claus machine comes to a halt and one Muckla catches a wheel and disappears with it.