Shelah Fane, a motion picture star who is filming in Honolulu, consults the mystic Tarneverro, her spiritual advisor, to decide if she should marry Alan Jaynes, a wealthy globetrotter whom she met on the ship to Hawaii. During a crystal ball session, Shelah confesses to Tarneverro that three years earlier she fell in love with her co-star, Denny Mayo, and that she was in his house on the night he was murdered.
Agitated following her consultation, Shelah tells Julie O’Neill, her protégé, that she cannot marry Alan. Anna, Shelah Fane’s maid, is greatly upset when, as she brings Shelah an orchid corsage from stage actor Robert Fyfe, who is currently appearing in town, she sees Shelah tearing up a photograph of Denny Mayo.
That evening, just before a dinner party that Shelah Fane is giving, Julie, along with Jimmy Bradshaw, a tourist bureau employee who wants to marry Julie, find Shelah stabbed to death in her pavilion. Without explaining why, Julie has Jimmy remove Shelah’s emerald ring.
During his investigation, Inspector Charlie Chan finds the orchid corsage crushed next to the actress’ body with their pin missing. He also notices in the sand outside the pavilion a footprint made by a shoe with a hole in it. Chan gathers the guests, all of whom were in Hollywood at the time of Denny Mayo’s murder, and relates the old saying: “Death is a black camel that kneels unbidden at every gate,” adding, “Tonight, black camel has knelt here.”
Chan’s blundering assistant Kashimo finds the pieces of the ripped photograph of Mayo, which disappear during a scuffle in which the room is plunged temporarily into darkness. When Kashimo brings in a beach bum who calls himself “Smith,” and whose shoes match the footprints found outside the pavilion, Fyfe, Shelah’s ex-husband, suddenly confesses to Shelah’s murder. Alan, greatly upset at being detained, and declaring that Fyfe’s confession resolves the case, wants to leave immediately to catch a boat to the mainland. However, Chan deduces that Fyfe could not have been at the pavilion at the time of the murder, and warns none of the guests to leave the island.
In need of money, Smith, who is an artist, threatens Fyfe that he will tell what he overheard Shelah say in the Pavilion unless Fyfe buys one of his paintings. After Fyfe gives him $100 with the promise of an additional $200 later, Smith is shot by an unseen assailant as he walks along the beach. He staggers to a shack on the beach where his native girlfriend, Luana, comforts him.
At Jimmy’s urging, Julie confesses to Chan that she took the emerald ring because it contains an inscription from Mayo. She tells him that she had wanted to keep Shelah’s relationship with him a secret.
The next day, Chan learns from Mr. and Mrs. MacMasters, an Australian couple who know the renowned psychic, that Tarnverro is really Denny Mayo’s brother Arthur.
Luana accuses Fyfe of shooting Smith, and takes Chan and Fyfe to her shack on the beach where the artist lies dying. Before Smith dies from his gunshot wound, he reveals to Chan that he had overheard Shelah Fane tell Fyfe that she had confessed to Tarneverro that she had killed Denny Mayo. Fyfe confirms this and says that after Shelah had found out that Mayo had a wife in England, she shot him during a quarrel. Fyfe tells Chan that he had confessed to her murder because he still loved her and wished to protect her memory. Smith also reveals that he took a diamond pin from the pavilion that he had found next to the crushed orchids, which, Chan notices, has a missing pin.
Back at the house, Chan finds scratch marks on the floor beneath the dinner table that he believes were made by the shoe in which the missing part of the diamond pin, embedded in the murderer’s shoe when the corsage was trampled under foot, is probably still lodged. As he makes this discovery, a knife is thrown at him. Chan deduces that Fane’s murderer must have sat in the chair situated above the scratches.
Meanwhile, Julie accepts Jimmy’s proposal and agrees to remain with him in Hawaii.
Later, Chan has the suspects sit at the table in the same positions in which they had sat the previous night. Tarneverro sits at the chair nearest to the scratches, but upon further investigation, Chan learns that later that night, the maid Anna sat in the same chair. When Chan finds a piece of the diamond pin embedded in the heel of her shoe, she reveals that she is Denny Mayo’s wife and that she killed Shelah Fane. Tarneverro tells that he came to Hollywood to find his brother’s murderer, and that when Shelah confessed to him, he told Anna. He asks to share Anna’s fate. As Chan goes to arrest Anna, Jessop, the butler, who is in love with her, pulls a gun. After a brief struggle, Chan disarms him. Jessop then admits that he shot Smith because he knew too much and that it was he who had thrown the knife at Chan.
Just then, Kashimo enters with a clue, but Chan instructs him to “save for next case.”