The Office of Planetary Security was the Protectorate of Grayson's domestic security and investigation agency answerable to the Protector. One of its divisions, the Building Safety Directorate, investigated the collapse of the sabotaged crystoplast dome of the Winston Mueller Middle School in Mueller Steading. (HH5) The OPS investigated Steadholder Mueller for a number of crimes, and even planted a deep-cover agent within his personal guard. (HH9)