Hurray! Holly, Tracy and Belinda will spend their holidays in hot California! In addition, Tracy has a special mission: she must transfer a relic to the museum of the Oseo Indian tribe - the encrypted diary of gold miner Jack Foster, her distant ancestor. Once he bequeathed all the gold from his mine to the Indians who saved him. And the time has come to fulfill the will. However, the diary disappears from the hotel room where the girls are staying. And its value is great - because by deciphering the records, you can find out where the gold is hidden! The detective club begins an investigation - after all, it seems that someone has been seized by the gold rush again...