From back cover:
Treasonous elements in our society have discovered a potentially dangerous biochemical supplement which they wish to introduce into our food supplies. They call it Af-ro-dee-see-ak. Its effects are unknown.
Your mission, whether you like it or not, is to guard the food vats from sabotage while preserving the machinery and personnel in the food vat area. You will have no trouble accomplishing this mission - The Computer says so.
One final, unimportant note: please sign all Release From Damages and Pre-Treason Execution Vouchers before reporting for your briefing. Thank you for your cooperation.