Mr. Moto’s Last Warning

Fabian's plan is to blow up the French ships and pin the blame on the British, which would incite conflict between France and England. The sabotage is meant to destabilize the British and French governments by creating an international incident that would turn the two allies against each other.

Earlier at the variety show, Fabian gathers his gang of saboteurs and discusses their conspiracy to disrupt the naval exercises.

Danforth is actually Richard Burke, a British Secret Service agent working undercover. Fabian discovers this identity and uses it to lure Burke to his death, eliminating a key threat to the sabotage operation.

Danforth's suspicious behavior and knowledge of secret operations hint early on that he is more than a simple bystander.

Fabian lures Burke (Danforth) to the salvage ship The Vulcan and traps him inside a diving bell. Once trapped, the bell is lowered into the water, suffocating him. This murder eliminates the British agent who was working to expose the conspiracy.

Fabian's discovery of Burke's true identity as a British agent creates the motive for eliminating him.

The impostor is Mr. Kuroki, a fellow agent working with Norvel, who disguises himself as a curios dealer. Kuroki impersonates Mr. Moto as part of the espionage operation, but Norvel eventually kills him after exposing his cover, making it appear that the real Mr. Moto has been eliminated.

The fake Mr. Moto arrives on the ship and quickly becomes a target for the conspirators.

The Vulcan is a salvage ship commanded by Captain Hawkins, who is part of Fabian's sabotage gang. It serves as the location where Fabian traps and kills Burke (Danforth) using a diving bell. The ship is central to executing their plan to eliminate British agents.

Mr. Moto learns about The Vulcan from the Port Commandant's office during his investigation.

Moto chooses not to disclose which country was behind the sabotage plot, emphasizing the delicate balance of espionage and diplomacy. Revealing the perpetrator could escalate international tensions or compromise ongoing intelligence operations.

The conspiracy involves multiple foreign agents, making the true sponsor ambiguous throughout the investigation.

After being tied up in sacks and thrown into the ocean, Moto escapes underwater by freeing himself from the bindings. He then frees Venables as well, and they fight off the saboteurs in the water before Moto seizes a sharp piece of metal to use as a weapon.

Moto's resourcefulness and training as an International Police officer prepare him for suchdangerous situations.

Connie, Fabian's girlfriend who was unknowingly used to spy on Moto, witnesses the violent confrontation between Moto and Fabian. During the climactic fight, she intervenes by shooting Fabian to stop him, revealing her bravery and choosing to help Moto over her boyfriend.

Connie previously tried to alert authorities about Fabian's plans after overhearing their sinister schemes.

Norvel is an agent working against the British Secret Service. He befriends Madame Delacour to gather intelligence about when the French fleet will return to port, feeding this information to Fabian to help time the sabotage operation.

Norvel's humorous demeanor hides his true motives as he quickly reveals his spy identity when the ship docks.

Fabian becomes suspicious that Kuroki (the disguised Mr. Moto impostor) could actually be the real Mr. Moto because of his mysterious behavior and investigation. This suspicion drives Fabian to put Moto under surveillance and eventually attack him.

Kuroki's presence and actions in Port Said make him a suspect in Fabian's eyes.

Moto intercepts the explosives meant to destroy the French fleet and detonates them prematurely, ruining Fabian's plan. He then fights Fabian directly until Connie shoots the villain, effectively ending the conspiracy to destroy the French ships.

Moto's investigation throughout the movie builds toward his interception of the explosives.