The script for the series was written by Astrid Lindgren, who later re-wrote it as a book, also titled Vi på Saltkråkan (published in English as Seacrow Island in 1964).
The series tells the story of a family from Stockholm, consisting of the widowed author Melker Melkersson (Torsten Lilliecrona) and his four children: 19-year-old Malin (Louise Edlind) who assumes the role of mother in the family, the imaginative 13-year-old Johan, 12-year-old Niklas who is calm and down-to-earth, and 7-year-old Pelle, who loves animals of all kinds.
The Melkersson family spend their summer holidays as well as some winters on Saltkråkan, an idyllic place symbolising the unspoilt archipelago.
The Melkersson children become friends with the local kids: Tjorven (actually Maria) Grankvist who is the same age as Pelle and who owns a huge St. Bernard dog named Båtsman (Boatswain), her older sisters Teddy and Freddy who teach Johan and Niklas to row and sail, and Stina, a gap-toothed Stockholm girl who spends her summer holidays with her grandfather, and who tells endless stories to the long-suffering adults around her.
Astrid Lindgren added the character of Stina to the script when Olle Hellbom had met Kristina Jämtmark and thought that she would make a good addition to the group of children.