Basin Keep is a location in CrossWorlds, and the fourth city reached in the game. It is a city of tall buildings and neon lights, located on an island in the middle of Gaia's Garden. The weather here is always dark and rainy.
Basin Keep is a city build on a small island amidst a huge lake in the center of Gaia's Garden. Its a technological wonder only possible by the through its location and many safety mechanisms. To make sure the jungle does not creep into the city, the outside walls are engulfed in a special alloy which fends off most plants.
The city grew large very fast as it became the main supplier for clean electricity that meets the demands of humans on Shadoon. Many Bars and luxurious penthouses can be visited or rented respectively. Basin Keep is often viewed as gloomy since it is always raining and the high buildings leave the city in a permanent dark setting. Still many prefer the more urban nature of it compared to bright cities like Rhombus Square.
There are three main areas in Basin Keep. The central area holds a trader marketplace, as well as shops and the seeker hub. To the east is a slum area, with several black market sections which require a pass to access. The western area of the city is an upper-class neighbourhood.
Gaia's Garden (via Centrum and a teleporter in the Woodland Vanguard HQ)
Most of the rooms in Basin Keep are accessible immediately, with the exception of the Clipson Tower (unlocked during the Hostage Situation and High Crating quests), the Calzone shop (unlocked after the Sprouting Business quest), the Boosi Business (unlocked during the Pumpkin Land Superfun quest) and the mayor's office, which is unlocked while progressing the plot. However, some sections of Pond Slums are the black markets, which cannot be entered unless you have obtained a Pond Slums Pass from the Mushroom Kingdom quest.
The Sprout of Spirit rare destructible is in the top of a building in the upper right corner of the Pond Slums. You need the Pond Slums Pass and have to destroy some trash bags to reach it.
The Trash Bag destructible does not show up in the Botanics menu, and the trash collected from it has no use in-game.
Many of the rare equipment traders are located in the slums black markets, and the Pond Slums Pass obtained from the Mushroom Kingdom quest is required to reach them.
It is not initially required for Seekers to visit Basin Keep on their way to the Grand Krys'kajo. However, after finding the temple complex barricaded by Shad protesting the power plant, they must return here to attempt to bargain with the Mayor. The Mayor is not overly concerned with what he views as the Shad's nonsense, but under protest from K'tara, he tasks the Seekers with assisting with the problem, in the mandatory An Infested Village quest.