In this story, Tigerlilly, known from the play "The Strongest Adventures of Little Tigerlilly", experiences a completely new adventure as "Pirate Lilly". For her birthday, she and her sister Leo are given the task of finding a treasure that contains their shared birthday present. The two girls don't like having to share the treasure at all and decide to go on the journey individually. The person who finds the treasure first gets to keep it.
During her adventure on the pirate island, Pirate Lilly gets to know many animals who ask her exciting puzzles in order to get closer to the much sought-after treasure. She also meets her friend Björn the Bear, who is head over heels in love.
On her journey, Pirate Lilly learns that sharing often brings joy. And that most things are much more beautiful when you experience them together.