The action takes place in Piran, where three children meet. An SMS message was sent to the wrong number triggers a series of events in which children go through various adventures and puzzles related to Piran. The antagonists of the story are bandits who are looking for treasure, but they are overtaken by children who are more skilled in solving the keys that lead to the treasure. The children are the first to find the treasure, which is actually a collection of letters between the famous violinist Tartini and Stradivari, a violin maker who through correspondence provided him with support and advice on improving violins.

Story is based on a novel of the first Slovene female writer from the 19th century when also the story of the film is set. It's a never-ending and forever repeating story of neighbors, who can not reconcile. As they need the fight to stand out for their position of "neighbors", as that's the ultimate and only role of people living next to each other being called neighbors.