After Kat awakens in Hekseville, she reasons that she needs to find a place to stay. As she explores the city, she falls through a manhole and tumbles into the sewers, where she finds a large pipe that she decides would make a perfect home. She proceeds to furnish and decorate the pipe, making it into her house. From this point on, the house serves as a spot for the player to save their game and change Kat's costumes.
After the events of the first game transpire, Cyanea moves into the pipe house with Kat, where she can frequently be seen nodding off in the chair.
Upon Kat's return to Hekseville, she travels to her pipe house only to discover that it has been filled with garbage, and that her old bed is infested with bugs. A police officer arrives and demands that she leave, as the house is not registered to any citizen. Incensed, Kat leaves.
From this point on, the player can use Kat's home as a manhole warp point and as a means to replay previous story missions and side missions. The player can also decorate the house using furniture obtained by completing side missions, challenge missions, or treasure hunts.