The Lake is old and alive. Many creatures live with it. In a sense, the creatures are the Lake, and the Lake is its creatures. Humans discovered it and set up a base to try to understand the Lake.
Humans have learned a few things about the Lake, but many mysteries remain. The creatures seem to communicate using invisible particles called memory cells. The lake color-codes its water to let creatures know whether they're in the right place. There are creatures which clean up the lake, creatures which guard it, creatures which collected the dead creatures, creatures which feed other creatures: they work as one body, as one system, although there are also many creatures whose role is unknown to the humans.
For this reason, the humans are reluctant to meddle with the Lake, until the Lake begins to create creatures which look like humans. These "Lake-humans" hide themselves from the humans, but one was captured by them. Venus.
The Lake is large. It covers much of the planet. It is bigger than any lake on Earth, but not as big as an ocean. It will take a long time to explore. It will take a long time to learn about. The player should proceed slowly but with confidence.
In the center, there is a relatively peaceful area. This is where Venus was found.
One part of the lake is full of creatures, heavily populated.
Another area is full of whirlpools, and is hard to navigate because the strong water and wind currents can push the |Leta| around.
Another area is full of dead creatures and vines. It is here where creatures are revived after they die.
Another area is full of steam and small volcanoes, and is often so full of darkness and ash that it is hard to see for long distances.
Another area is cold and full of ice and icebergs, with few creatures and relatively little water to navigate through.
Another area is full of flowers and the creatures which tend them. This area brings life to the Lake by collecting energy from the stars and converting it to food for the creatures.
Another area is rocky and undeveloped, with almost no creatures. It is here that the humans have set up their research base.
The cave is also ringed by a network of caves and tunnels surrounding it, which connect the edges of the Lake and contain it. If these are reached, the |Leta| could navigate the lake quickly, like a highway around the Lake. Reaching it will be difficult though, because the Leta begins in the center of the Lake.