Crei Imperative
From Tardis Wiki, the free Doctor Who reference
The Crei Imperative took the city of Prague out of the 24th century in a time trap in order to find their missing Tipping Device. They planned to use it to wipe out their enemies. Sergeant Kandula hid it from his superiors and, with the help of the Third Doctor, removed the Tipping Device from Prague. (PROSE: Midnight in the Café of the Black Madonna)
