The cave consists of a series of passages leading to a main chamber, where Jackson communicates with Professor Calvert. The sea cave is inhabited by swamplurks, mirelurk hunters, and swamplurk queens. Additionally, a lone unnamed friendly Tribal wanders the cave and will follow the player around if he spots the player. However, the Tribal will often be killed by mirelurks before the player encounters him.
In the final room you may occasionally hear splashing of items dropping into the water pool, this is due to the final room being based below the graveyard, and every so often a skeleton will fall from the roof of the cave.