Black Lizard

In Yamakawa's room, Sanae is brought there as part of a wedding doll viewing. Yamakawa drugs her with chloroform and stuffs her into a trunk, abducting her from her life with her father Shobei Iwase. The kidnapping sets the plot in motion.

Detective Akechi explains that Yamakawa is actually Junichi Amamiya, a depressed man manipulated by Black Lizard to abduct Sanae. He orders his men to track Amamiya and succeeds in recovering Sanae. He also reveals that Mrs. Midorikawa is Black Lizard in disguise.

After the kidnapping attempt, Black Lizard slips away from the hotel wearing men's clothing to escape unnoticed. The disguise helps her move freely as investigators close in. The escape marks the villain's evasion from immediate pursuit.

Sanae is kept at her father's house and told to stay in her room. Housekeeper Hina and another worker plot to kidnap her, escalating the danger surrounding Sanae. Iwase's guard Matobe tries to intervene but is overpowered, losing his hand and leaving blood on the new sofa.

Iwase demands the sofa's removal, and his staff discreetly takes it away while secretly sliding Sanae out through a hidden compartment beneath the seat. The covert extraction allows Sanae to vanish from view once more. This action deepens Iwase's involvement in protecting his daughter.

Black Lizard sends a note demanding the Star of Egypt, a priceless gem, in exchange for Sanae's return. The gem becomes the focal point of the mounting confrontation between the captor and Sanae's family. The threat raises the stakes for all involved.

Noon on August 4, Iwase brings the Star of Egypt to Black Lizard at New Shinonome pier, hoping to secure Sanae's return. Black Lizard pretends that Sanae will be returned that night, creating a false sense of resolution. The staged exchange sets up the next move toward the island.

On a ship bound for a private island, Sanae is seized and taken away. Inside the sofa's hidden compartment, Akechi overhears Black Lizard talking, complicating the plan. In response, Black Lizard pierces the compartment with a sword and orders the sofa thrown overboard; Junichi Amamiya is revealed to be in disguise as Matsukichi.

On the island, Black Lizard unveils a collection of preserved human bodies arranged as statues. Junichi Amamiya tries to help Sanae escape but is captured and thrown into a cell with her. He learns that Yoko Sakurayana is Sanae's double and, choosing to stay with her, agrees to become one of Black Lizard's dolls; the two fall in love.

Black Lizard becomes furious after reading a newspaper article announcing Sanae's return to her father. The public acknowledgment complicates her plans and raises the stakes for everyone involved. The shift in perception heightens the dramatic conflict on the island.

Akechi calls in the police and reveals his true identity to Black Lizard. He frees Junichi and Yoko and allows them to leave the island to start a life together. The revelation marks a turning point as the couple gains a chance at a future beyond the island.

Hina makes a move by releasing a poisonous snake toward Akechi, but Black Lizard stops her by impaling Hina with a sword. The act demonstrates Black Lizard's ruthless control and she hastily retreats back to her room.

Akechi reveals that Black Lizard killed the real Matsukichi in the sofa compartment. She then confesses that she has consumed poison, whereupon she dies, bringing a violent end to her reign of manipulation. The revelation ties up the final loose ends of the tale.