Lisbon, 1925. A young con man named Alves dos Reis brings the Bank of Portugal to its knees through a scheme as insane as it is brilliant: printing millions of authentic banknotes - bearing forged signatures. But behind his ambition lurks something far darker: an international network manipulating global finance, orchestrated by unseen minds and occult forces.When the case reaches the ears of Sherlock Holmes, now retired in Sussex, the lure of the enigma proves irresistible. By his side stand old and new allies: Dr Watson, more resolute than ever; Arsène Lupin, the gentleman thief with impeccable instincts; Augustus S. F. X. Van Dusen, the "Thinking Machine" who deciphers economics like a theorem; and the enigmatic Three Just Men, shadowy judges fighting the abuses of power.From Parisian galleries to the tunnels beneath Chinatown, from masked balls in Yorkshire to hidden vaults under London, the protagonists confront a financial conspiracy that foreshadows the Great Crash of '29. Banking intrigue, secret societies, proto-algorithms and coded messages intertwine in a high-stakes investigation that blends classic mystery with historical thriller and intellectual adventure.