A terrific storm overturns the characters’ galley and they are left floundering amidst the deafening fury of the waves. The next morning they are washed up on an island. From the sea they can see a small jetty set into the cliffs, and on the far side of the island, they might just glimpse a short tower, its windows glinting in the morning sun.
At the jetty all they will find is the rotting hulk of a rowing boat half-filled with putrefying carcasses and dismembered limbs.
The island seems to be deserted, but they will soon encounter the weird and twisted fauna: primarily manticores and other magical hybrids. There are some paddocks and cages around the island, some of which are broken open, others still intact, containing starving creatures.
The tower and island belongs to Panath Aesiron, a young wizard who fled from the mainland years ago having stolen the Erikathikon, the first of the infamous Blue Books of magic. He experimented with the magics he found inside its covers, forging unpleasant lifeforms from limbs he had delivered from the mainland, always believing he was furthering the cause of science and magic, ever deepening the pit he had dug himself.
The last page of the Blue Book details the creation of a particularly evil horror, to which no name is attributed. It is this creature which he spent his last weeks creating, neglecting his other creatures. Eventually it turned on him and killed him.
Around the island may be found leaves from Panath’s diary which have blown from his study desk through an open window, detailing his last days: how he could hear the screeches of the other creatures when they escaped their cages, how they howled and bristled when he tried to feed them, sensing the evil on his hands, and the final page which the characters will find in the study of the tower itself, where in his last moments, he described the silence of the other creatures when the nameless horror escaped from his cellars, trapping him in his attic, hearing the scratching on the floor below…
One of the characters will be corrupted by the Erikathikon, and take it without the others knowing (the character could do this unconsciously through the power of the artefact).
The last big battle could be with the nameless thing in the cellars.