Charlie Chan in Panama

Godley arrives in Panama City with the new group of suspects arriving by seaplane bound for Balboa, signaling that danger is imminent. He seeks Charlie Chan's help and goes to Fu Yuen's hat shop to enlist the sleuth's services in unmasking the spy known only as Reiner. The setting is tense as the canal maneuver preparations begin and the city fills with undercover activity.

Shortly after the recruitment, Godley dies from a poison-laced cigarette, a method implying a fellow seaplane passenger among the newcomers. Chan must keep a weather eye on the suspects during their hotel holdover as he investigates the murder. The death casts suspicion on every arrival and accelerates Chan's investigation.

No.2 Son Jimmy Chan is arrested for taking pictures, but he quickly reveals details about his father's true identity. He is then found hiding under the bed in Clivedon Compton's hotel room, which raises questions about what he knows and who he's protecting. The incident puts Chan directly in the path of the suspect group.

A porcelain tobacco container in Compton's room hides a detailed map, triggering a deeper search of the room. The map points toward the Manolo family tomb, hinting that the residence there doubles as a spy hideout. The discovery tightens the link between the suspects and the canal sabotage plot.

Miss Finch blunders onto the scene at the tomb, and someone locks them inside, turning the graveyard into a trap. The tomb, rigged and connected to the ongoing intrigue, is part of the spy network's operations. Chan and the others must stay vigilant as the walls close in.

Disguised as a water delivery man, a henchman delivers a 'water cooler' filled with nitro to the Main Power Plant building. The timing aligns with the plan to sabotage the Miraflores locks, threatening the fleet and the canal. The tension escalates as the plot advances toward a deadly deadline.

During a graveyard chase, the henchman returns to the tomb, unwittingly releasing Chan, Jimmy, and Captain Lewis. This surprising release shifts the momentum of the case and tightens the chase through the tomb complex. The risk to the fleet remains high as doors reopen to new confrontations.

Chan learns that the Miraflores locks are to be blown at ten that night, creating a perilous deadline for stopping the sabotage. He races to coordinate the suspects and secure the devices before disaster strikes. The imminent explosion becomes the central pressure driving the investigation.

Chan sequesters the suspects at the plant, and Miss Finch exposes herself as Reiner in a bid to escape death, revealing her true identity. Security moves quickly to place Reiner under arrest, breaking the spy's hold on the operation. The perilous standoff culminates with the capture of the mastermind.

With Reiner under arrest, the fleet sails safely through the Miraflores locks, ensuring the canal remains open to navigate the Pacific fleet. Chan also reveals that he had previously defused Reiner's explosive device, averting disaster at the eleventh hour. Democracy is saved for another day as the canal remains operational.