As far as most people are concerned, Innsmouth Academy is a private coeducational boarding and day high-school (grades 9-12; ages 15 through 18) for privileged rich kids, situated on a tiny island off the coast of Maine.
In actuality, the Academy is an educational facility for secret worlders; more specifically, the children of secret worlders affiliated with the Illuminati, although the school sometimes admits exceptionally gifted students -- and faculty -- from other societies. It is considered one of the premier occult prep schools of the secret world, and a degree from Innsmouth Academy opens many doors for a budding magus and occultist.
Founded and constructed in 1798 (and rebuilt in 1852, 1906 and 1967, after, respectively, a devastating fire, an earthquake, and the opening of a dimensional portal in the elementalism lab) with investment from a group of mysterious benefactors -- ostensibly wealthy businessmen with local ties -- the Academy has endured, mostly thanks to a long row of dedicated headmasters and fiercely loyal faculty.
With a skeleton in every closet and deals with various devils inked into the very blueprints of the buildings, the Academy is an occult powderkeg primed to explode -- as it very nearly has during attacks in its past. Though the few survivors do what they can to bolster the wards, it requires a great, and unflinching, magical talent to plug all the leaks, and headmaster Hayden Montag has taken that responsibility seriously and single-mindedly.
Without outside assistance, however, Montag and his motley crew will not survive long. The fog -- and the things in it -- are gathering strength, and the Academy holds many secrets that would be of great value to those who can get their hands on them.