From time to time, one of the All can be divided from the One and All mind. This is a traumatic event, and it is rare that the severed member of the All survives, let alone becomes a solitary One. But from time to time, it can occur. Seeking succor from the desperate silence in its mind, the One Beneath The Waves has sunken himself beneath the oceans of Shamash II, and there it lies, seeking fruitlessly to soothe its injuries.
In the harbour of a major city a large and terrifying ship made of human nails docks. Nobody seems to inhabit this ominous vessel, someone needs to go on board and unveil the mystery. In comes the PCs.