Harriet & Will - the secret gold (The Secret Gold)

While on a school gold rush excursion, 11-year-old Harriet Cooper and her best friend Will Taylor are drawn to an old red phone booth, restored to play stories of the goldfields in return for an historic coin. The phone booth appears in the museum grounds of each location the children visit. But they discover much more and end up time travelling to each of the three Australian historical gold rush locations, obtaining information for their upcoming school history project.

When Harriet discovers some old gold coins at one museum and a nugget at a gold mine museum site, she is excited. Both the coins and the nugget have been missing for over 100 years, and the gold would help to pay off her parents' house. But Harriet may not be allowed to keep both, according to a tough teacher and assistant principal, who believe she is not entitled to it. Along the way, Harriet's personal bully tries to block Harriet's claims and keep the gold for herself.

With the assistance of their red dragon friend, Gruffyd, the two become involved in drama galore, from riots to threatening miners, tough teachers and more. It appears as though Harriet might lose her claim to ownership, and she and Will seek justice. Help comes in the form of a second protective dragon, who reminds Harriet that the gold nugget, called Da Jin Shi, is really her property now and something disastrous will befall anyone else who tries to claim it.

Harriet is cleared as the owner of the coins, but the gold mine museum wants the nugget returned for a display. However, she receives a substantial reward for its return, the offer of a buyer for the coins and everything is restored.