AllMovie

A low-security prison labor camp is about to be closed down due to the excessive brutality of the warden (Lee Frost), whose strict manner has embittered the convicts and damaged his career. The inmates are engaged in the production of formaldehyde, which they also use to get high by sniffing the fumes. While under the influence, a group of prisoners begin digging a secret escape tunnel, and they threaten their non-huffing bunkmates with death if anyone exposes their plan. The getaway attempt is thwarted by overzealous prison guards, and the escaping prisoners are shot down and buried in a nearby cemetery. However, the massive exposure to formaldehyde has a curious effect on the corpses; they won't stay dead and they crawl from their graves to exact bloody revenge upon the prison camp. The zombies arm themselves with axes, shovels, and dangerous lawn-care items from the prison tool shed, while the living convicts have to join forces with the warden and his guards in order to stay alive. Also known as Garden of the Dead.