When a single shot rings out to shatter the quiet at a prominent museum, it signals the start of a new mystery Patricia Fisher cannot avoid investigating.

An apparent suicide, a missing woman, a sunken treasure ship worth billions, and suspicious behaviour from almost everyone she meets ... well, that might be a lot to take for some people.

For Patricia Fisher, it's just Thursday.

She's in Rio on the trail of an altogether different mystery, however it's not long before Patricia questions if the two cases might not be intertwined.

What did happen to Professor Noriega?

Was his death a terrible accident?

If so, why was there a man onboard the Aurelia pretending to be the professor?

With faithful companions at her side, our English sleuth will have to roll the dice and take some chances for she only has two days to uncover the truth.