On the remote island of Fara, off the English coast, Jeff Callum, a professional novelist, and his wife Frankie Callum run The Swan, an inn perched at the edge of the sea. When Jeff hires a secretary to handle his work, he discovers it is Angela Roberts, a younger woman with whom he once had an affair, who has arrived on the island intent on tempting him away from his marriage or at least stirring trouble in it. Frankie wonders if the change of scenery from the mainland is enough to cure their tedium, while Angela’s presence quietly fuels a growing tension that unsettles everyone on the island.
The atmosphere soon grows oppressive as a heat wave grips Fara in the middle of winter, turning the ordinary into the extraordinary. Cars stall, bottles shatter, televisions fizz, and telephones go dead as temperatures rise beyond reason. Into this charged, surreal heat steps Godfrey Hanson, a mysterious scientist from the mainland who rents a room at The Swan. He spends his days wandering the island, setting up motion-sensitive cameras and collecting soil samples. The locals—including the Callums—watch him with suspicion, sensing that there is more happening on Fara than a simple heat spell.
Suddenly, a series of disturbing occurrences intensifies the unease: a tramp is burned to death in a cave by a strange, high-pitched whirring sound; a farmer reports his sheep are dead in a way that seems scorched from within; and Bob Hayward, a Swan regular, is attacked on the road, blinded by a bright light and crashing his car into a blaze that threatens the fuel. In the pub, Tinker Mason, already fraying from the heat, tries to strike out at Angela Roberts, only to flee and perish in flames when she defends herself with an heavy ashtray. Jeff confronts Hanson and demands answers, and Hanson reveals a chilling theory: Fara is the site of an extraterrestrial invasion, with beings whose extreme heat burns anything that comes too close.
Hanson proposes a plan, and the group—joined by the island’s physician Dr. Vernon Stone—moves toward a coordinated defense. Stone’s attempt to reach Fara’s meteorological station to warn the mainland is thwarted by the alien presence, and he is killed. The panic deepens as Stella Hayward, Bob’s wife, is killed, confirming that the invaders are attracted to light. At the weather station, Ken Stanley and his colleague Gerald Foster reveal that the aliens have already killed the communications operator and destroyed all contacts, isolating the island.
With time running out, Hanson, Jeff, Frankie, Angela, and the others devise a risky gambit: they will lure the aliens with a bonfire of hay in a field, then drop dynamite to annihilate them, while flare pistols will signal for help. The plan is ambitious but perilous, and it quickly unravels as casualties mount—Foster and Hansen are killed in the ensuing chaos. Surrounded by the deadly beings, the group faces a bleak outcome until a sudden thunderstorm sweeps in. Rain proves fatal to the invaders, and in the downpour, Jeff, Frankie, Angela, and Ken survive the ordeal, their ordeal on Fara ending with a fragile, hard-won return to safety.
The story unfolds with a measured, eerie pace that blends domestic tension with an otherworldly threat, highlighting how a small community grapples with the unknown amid extraordinary weather and inexplicable events. The characters’ relationships are tested to the limit, and their fates hinge on courage, quick thinking, and a last, desperate hope that nature itself might turn against the alien presence that menaced them all.
