Lupin the Third vs. Detective Conan

Queen Sakura was not killed in a hunting accident as it appeared. She was actually murdered by her own brother, Gerard Musca Vespaland, who was the Prime Minister of Vespania. He killed her and her son Gill to seize the throne and profit from forbidden ore located beneath the kingdom.

Gerard Musca Vespaland, Queen Sakura's brother and the Prime Minister, orchestrated the murder of both the Queen and her son Prince Gill. He framed it as a hunting accident and then used the political crisis to consolidate power for himself while profiting from the forbidden ore beneath Vespania.

Ran impersonated Princess Mira after the poisoning attempt at the festival was exposed. The real Mira and Ran swapped places as a security measure, but when Mira needed to return to the party scene to explain the situation, Ran was left continuing the impersonation to avoid a diplomatic incident, forced by Duke Keith to maintain the ruse.

Lupin used dowsing rods to locate a valuable mineral deposits beneath Vespania, which led him to discover the vault under the palace where the crown was stored. This mineral was the same forbidden ore that Gerard Musca was secretly mining for profit.

Fujiko Mine arrived at the vault before Lupin and already had the crown in her possession when he arrived. This unexpected move forced Lupin to flee with Goemon as alarms triggered, creating a twist in their usual dynamic where Lupin is typically the one pulling off the heist.

Although Lupin and Conan are natural rivals, they temporarily teamed up because their goals aligned, both wanted to expose the true villain behind the political crisis. Lupin had his own reasons to investigate the conspiracy, and working with Conan helped him achieve his objectives while also bringing justice to the murder plot.

At the end of the film, Lupin reveals he knows Conan is actually Shinichi Kudo. The Japanese embassy officials who escorted Conan back to Japan were revealed to be members of Lupin's gang. Lupin acknowledges their connection and promises to meet again under different circumstances, leaving their rivalry open-ended.

In the epilogue, Fujiko closely examines Conan's transformation and the effects of the APTX-4869 drug that shrank him to his child form. Her scientific interest in the drug's properties suggests she may be researching it for future plans or simply finds the phenomenon fascinating given her association with Lupin's criminal world.

The mineral beneath Vespania was a forbidden ore that Gerard Musca was secretly mining for personal profit. This same ore was the reason he murdered Queen Sakura and Prince Gill, to maintain control over the mining operation and keep the profits for himself during Mira's reign.

Prince Gill, Sakura's son, took his own life out of overwhelming guilt. He believed he was responsible for the hunting accident that killed his mother, even though it was actually staged as murder by Gerard Musca. His suicide was a tragic consequence of the conspiracy.

After the murder conspiracy was exposed and justice was served, Inspector Zenigata chose to end the chase with grudging respect for Lupin. Since Lupin had helped solve the murder case and returned the crown to Queen Mira, Zenigata recognized that pursuing him further would be unnecessary, acknowledging their long-running rivalry with a mutual understanding.

Princess Mira initially rejected the throne because she was overwhelmed by grief and guilt over her mother Queen Sakura's death and her brother Gill's suicide. She visited the site where her family died and struggled with whether she could fulfill her royal duties while dealing with such personal loss.

Conan noticed the ruse that Ran was impersonating Mira and immediately boarded the next plane to Vespania to pursue the truth. During the flight, he nearly suffered from hypothermia but was saved by Duke Keith, who recognized Conan was on the side of justice despite being a detective in pursuit of Lupin.