A magical portal of great power, the Goulburn Hellmouth, conveniently located under the quadrangle of Mulwaree High, is known for being the oldest Hellmouth on the planet. As such, it is intensely powerful, and has only been prevented from being opened by 'chance' occurances orchestrated by the Powers That Be. Of its many abilities, the Hellmouth is most known for emitting an aura of evil which attracts demons and evil beings to its location. For the past three hundred years, the Hellmouth has been safeguarded by the Davidson Family.
Historically used as a portal between dimensions, the Hellmouth has such power that the Dimensional Barrier around it is far weaker than anywhere else. Because of this, the laws of nature, particularly physics and the basic laws of luck, are often warped around Goulburn. The Hellmouth is particularly known in magical cultures for being the final gateway through which the Old Ones left this Dimension, as well as spurring the creation of the Slayer line by the ancient Elders of the Australian Aboriginals. The Hellmouth has long been an important magical battle site between good and evil, and has been closely watched by Elders, Whitelighters, Witches and other, similar forces of good over several milennia. Currently, the Elders have assigned the Davidson Family to survey the Hellmouth and prevent it being opened. Whether or not the Elders possess the power to close this particularly powerful Hellmouth is unknown, but it is theorised only the power of the Charmed Ones coupled with the abilities of several Champions of the light may close it.
Conveniently located under the quadrangle of Mulwaree High, the Hellmouth exerts a magical pull over the community, prompting many young demons to the school, as well as attracting a like number of young witches to protect it. Because the Dimensional Barrier is thin in the area around the Hellmouth, Quantum Physics and Murphy's Law often take precedence in the school.