Five Dolls for an August Moon

Stark's business partner and Marie's husband, Nick is brusque and controlling. He resents Farrell’s invention and the possibility of losing control over the profits, yet shows a willingness to bend rules to secure wealth. His volatility and hostility toward his wife’s relationships contribute to the island's tense mood, and his eventual murder marks another step in the deadly unravelling.

A brilliant scientist who guards a revolutionary resin formula, Farrell destroys the original documents to prevent misuse. He is coerced by the guests with tempting cheques, challenging his conscience and loyalty to science. Farrell becomes a central target as the group schemes to force his hand, and the murky truth about his invention and its rightful inventor gradually comes to light.

Marie is Stark's coquettish wife who pursues new lovers and openly navigates the complex web of infidelity on the island. Her affair with Jill is a focal point, illustrating the corrosive effects of desire and vanity among the guests. Marie's fate is sealed by the escalating violence that follows the uncovering of everyone's secrets.

Peggy is Jack's wife and represents the couple who seem most stable at the outset. She becomes a victim of the island's escalating peril, shot on the balcony and later placed in the cold storage. Her death underscores the reach of greed and jealousy that permeates the group.

Jack is Peggy's husband and one of the more ruthless players who finally exposes the plan to steal the cheques. He arrogantly admits to killing others but is eventually killed himself in the final confrontation. His ruthlessness and fear of losing wealth drive a fatal confrontation with multiple winners and losers.

Isabel is Stark's teenage daughter, whose youth hides a sharp, calculating mind. She manipulates Farrell to confess and ultimately seizes the cheque and formula for herself, surviving the night and leaving with wealth she never anticipated. Her actions reveal a child of privilege who uses wit and audacity to reframe the family's fortune.

Charles is Stark's manservant and one of the few who crosses social boundaries to engage in a forbidden affair with Marie. He is discovered dead on the beach and is subsequently placed in the freezer, marking one of the first killings and signaling that no one is safe.

Trudy is Farrell's wife who harbors her own affair with Jill’s husband and becomes entangled in the plan to protect Farrell’s invention. She survives the rising chaos until the end, ultimately dying in a gun duel during the climactic exchange. Her actions help shape the final outcome and the mystery’s resolution.

Stark is the wealthy industrialist whose island retreat doubles as a stage for coercion and control. He is aggressive in his pursuit of Farrell’s formula, manipulating the other guests to secure leverage over the invention. He meets his end at the hands of Jack, a pivotal moment that marks the collapse of his empire of influence.

Jill is Stark’s artist wife who becomes entangled in a forbidden affair with Farrell. Her presence embodies the artistic, liberated side of the island’s dynamics, yet she also falls victim to the murder spree, dying in her bathtub as the mystery deepens. Her relationships illustrate how personal ambitions intersect with corporate scheming.