When state officials test out a new experimental pest-control device that uses subsonic waves to kill insects, it produces an unwelcome but interesting side-effect: the noise is enough to wake the dead -- literally -- and the corpses of the recently deceased begin to rise from their dirt-naps with ravenous appetites for warm human flesh. Since the predicted zombie jubilee starts off with more than a whimper than a bang (actually it's more of a wheeze, since these are particularly asthmatic undead), viewers are left with a rather mundane police drama as clueless detectives try to pin the mutilation murders on a group of free-wheeling hippies. Despite high production values and some audacious gore effects by Giannetto De Rossi (who would later lend his splattery talents to Lucio Fulci's Zombie and many more Italian zombie films), this Spanish/Italian co-production falters in the middle thanks to sluggish pacing and dull investigation scenes, which are devoid of suspense since the zombies' existence is already made known. Also released under the quaint title Breakfast at the Manchester Morgue, among others.
by Cavett Binion synopsis