But while all that is going on, Dr. Sheila Baxter, convinced that the center of independent thought is not the brain, but the forehead, starts experimenting on her colleague Dr. Philip Latham (whom he also has an affair with).
In the meantime, two sailors who have arrived in town, Big Dan Frater and Dutch "The Swede" Annacrombie, strike up a friendship with librarian Millie Healey, and start to notice the increasingly strange activities of the townsfolk, who are quickly taken over by the foreheads.
Nick's moll and local bar singer Droxy Chapelle seduces a drunk Big Dan, and get him to open the freezer where his boat's cargo - human cadavers ferried for medical research - are stored, and steal their foreheads.
Philip confesses his infidelity to his wife, Mary, but continues with the experiments, turning into a horrific monster with a giant forehead, and running away screaming.
Millie finds information in a book that various sound frequencies hurt foreheads, and she and the sailors arm themselves with bells, successfully repelling the attacking "bubbleheads".