Moving away from the apocalyptic horror of his 'Living Dead' trilogy, Romero reaffirms his equal aptitude for controlled chills, previously evident in Martin. Paralysed in a road accident, Allan Mann (Beghe) is provided with a trained Capuchin monkey, Ella, as home help. A research specimen before training, Ella had been injected with human brain tissue by Allan's mad scientist pal (Pankow) in the hope of increasing her learning ability. Now, as a result of a mysterious mind-meld, Ella responds to Allan's moods, violently enacting his frustrated rage against his bossy nurse (Forrest), fussing mother (Van Patten) and ex-fiancée (Turner), in nocturnal rampages which he experiences as hallucinatory nightmares seen through the monkey's eyes. Things build to a nasty climax when Allan falls in love with Ella's trainer Melanie (McNeil), triggering a violently jealous reaction from Ella. What sets this apart from most modern horror movies, besides a sparing use of special effects, is Romero's careful development of a credible emotional context for the pyromaniac madness and razor-wielding terror. Romero's is a formidable talent which others can only hope to ape.