A very young Jennifer Connelly stars as Jennifer Corvino, the daughter of an American film star, who enrolls in a prestigious Swiss boarding school. She learns that she possesses a unique telepathic gift - the ability to communicate with insects - but is prone to sleepwalking. In the film's opening sequence, set eight months prior to Jennifer's arrival - a young tourist is chased and beheaded not far from the boarding school. During Jennifer's first sleepwalk she witnesses another attack, though only remembers flashes of it, and ends up alone in the forest. There she is found by the chimpanzee assistant of a wheelchair-bound forensic entomologist, Dr. McGregor (Donald Pleasance), who takes care of her and enlists her to assist him with the investigation into finding the serial killer on the loose.
Jennifer's somnambulism becomes a concern for the school and is investigated by her tutors, including Mrs. Bruckner (frequent Argento collaborator Daria Nicolodi), and she is regarded as a freak by her schoolmates. When Jennifer's roommate Sophie becomes the next victim, Jennifer is again lured outside and is guided by a firefly to a maggot-infested glove. McGregor then identifies the maggots as those of the Great Sarcophagus Fly, which is drawn to decaying human flesh. Jennifer sets out with one of these corpse-hunting flies and tries to locate the killer's residence and places her life in danger as a result.
If it sounds bizarre and like it completely defies logic, then you're right. Argento is the master of building suspense and there are a handful of atmospheric, dream-like sequences here that will have you holding your breath. Just watching characters wander through old houses and forests, and be spied upon by unseen eyes (the eyes of the killer, usually) is enough to send shivers. With a throbbing electric soundtrack, courtesy of the unmistakeable sounds of Goblin (responsible for some of the great horror themes ever) and songs by Iron Maiden and Motorhead, the grisly murder sequences are heightened by these interesting choices.
As expected, Phenomena is brutal, and the opening murder sequence rivals some of the horrific killings in Suspiria and Deep Red. The finale is also tremendous, offering up a number of back-to-back shocks - and making use of a creepy underground lair and a knife-wielding chimpanzee. Argento has perhaps tried to utilise too many ideas, including a mix of police procedural, forensic science, psychoanalysis and paranormal events and though bringing all these elements together ensures it becomes an illogical mess, there is still plenty to admire about Argento's craftsmanship. Though far from his best, in my opinion, there are enough bizarre images to leave an acquainted Argento viewer with plenty to discuss and it features quite an impressive performance from Connelly.