Austin Wai plays Sum, a secret agent posing as the security chief of a remote mining colony where several employees have disappeared without a trace. At first Sum is impressed by the almost superhuman efficiency of the mine's workers, but soon becomes suspicious of the zombie-like manner in which the miners perform their duty. His worst fears are finally confirmed by the colony's resident physician (Deborah Sims), who has been forced to mix a powerful drug into the miners' meals that increases their strength while making them mental slaves of the company. Sum and the doctor prepare to expose the deadly secret, but with every other member of the colony out to get them, they may not live long enough to tell it.