Adam Sorg Gordon Oas-Heim is a struggling artist who lives in a house near the beach and wrestles with a hot temper fueled by critics who mock his use of color. He often vents his frustration on those around him, especially his girlfriend Gigi Elyn Warner. His fixation centers on finding the perfect shade of red, a quest that consumes him and shapes every choice he makes.
During a visit from local gallerist Mr. Farnsworth Scott H. Hall, a tense meeting ends when Adam smashes one of his paintings in a burst of anger. After Farnsworth departs, Gigi accidentally cuts her finger on a nail while picking up the broken canvas, staining the painting with her blood. This shocking moment awakens Adam to the red hue he has been chasing, and he asks Gigi to spill more of her blood to complete the unfinished work. He escalates by cutting his own fingers with a razor to gather more blood, pushing himself until he collapses from anemia, all while the painting takes on an eerie, living quality.
The next day, Gigi chastises him for using blood in his paint and for pressuring Farnsworth into praising an unfinished piece. In a burst of rage, Adam uses a painting knife to stab Gigi, killing her, and he proceeds to use her blood to finish the work. The following morning, after disposing of her body, he heads to the gallery to unveil the finished painting to Farnsworth. The art critic Gregorovich William Harris praises the piece, declaring it a masterpiece and requesting another painting, convinced that the artist has found his true calling.
Back at home, Adam prepares to draw more blood for another creation, and he spots a couple on the beach riding his hydrocycles. He climbs into a motorboat and pursues them, murdering them and using their blood to craft a new painting that he then exhibits at the gallery the next morning, continuing to blur the line between art and violence.
Time moves forward to a later day when April Carter [Candi Conder] heads to the beach with her boyfriend Rolf [Jerome Eden] and friends Jack [Jim Jaekel] and Sydney [Pat Finn-Lee]. While getting changed, April recognizes the reclusive artist and explains that her mother, Mrs. Carter [Iris Marshall], has been eager to own one of his paintings, despite his repeated claims that they are not for sale. Adam tells April that he is "looking for a model" and that he will give her mother a painting for free if she poses for his latest work. After some consideration, April agrees. Inside, Adam binds April’s wrists to a rope suspended from a ceiling beam, insisting that the setup will help her hold the pose.
Meanwhile, Jack and Sydney stumble upon Gigi’s decomposing body buried in the sand, and Rolf goes to the house to call the police. He arrives just as Adam prepares to kill April with an axe. In the ensuing struggle, Rolf grabs a shotgun from the mantle and shoots Adam in the face, ending his spree. The scene fades to Farnsworth burning one of Adam’s paintings, which appears to bleed as the film closes, leaving a haunting reminder of art’s dark price.
