'In the country of the Diamond-King'; English title: "Kingdom of Diamonds")[1][2] is an Indian Bengali dystopian fantasy musical film and a sequel to the 1969 anti-war fantasy musical Goopy Gyne Bagha Byne (and the second installment of Goopy Gyne Bagha Byne series) directed by Satyajit Ray.

They happily set out for the kingdom, dressed as commoners, unaware of the machinations of the King of Hirak (Utpal Dutt), who is a tyrant.

Those who protest are taken care of in the 'Jantarmantar'(যন্তর মন্তর), a chamber for brainwashing (মগজ ধোলাই) devised by the scientist (Santosh Dutta), who the king mocks calling as "Gobeshok Gobochondro Gyanotirtho Gyanorotno Gyanambudhi Gyanochuramoni"(গবেষক গবুচন্দ্র জ্ঞানতীর্থ জ্ঞানরত্ন জ্ঞানম্বোধী জ্ঞানচূড়ামণি) His ministers are mere puppets.

By coincidence, they meet Udayan hiding in a cave, who informs them of the king's true nature.

They request him to show them his impressive diamond mine, where Udayan, disguised as a miner, plant a note in Bagha's shoe while bowing to them.

While the inauguration of the large statue of the king, they check the note which is meet him in the jungle at night.

On reaching the laboratory, the king and his ministers are stunned magically by Goopy's singing and then pushed into the Brainwashing machine.

Ray said to The Times of India about the plot of the fourth film: "Making a Goopy Bagha movie without Tapen and Rabi is unthinkable.