A hypersonic device has been found at an embassy within spitting distance of the White House, and President Doyle thinks it may be the cause of Mara's violent episodes. Kevin, on the other hand, suspects something much more insidious: demonic possession. He gathers resources to prove to Father Reid of his sister's mortal danger but learns an exorcism may be just as dangerous for the recipient as it is for the practitioner. Can the First Family safeguard the citizens of the country they swore to protect from foreign influence? Can they save their own daughter from the denizens of Hell?