Final answer:
The siblings in "House Taken Over" throw away the key into the sewer at the story's end, symbolizing their surrender and final departure from their past lives and home.
Step-by-step explanation:
At the conclusion of "House Taken Over," the siblings throw the key into the sewer. This act symbolizes their acceptance of their fate and the relinquishment of their attachment to the house. They have been ousted by an unknown presence, and throwing away the key is a symbolic gesture of their surrender and acknowledgement that there is no returning to what once was their domain.
The key, being a symbol of ownership and control, being discarded denotes that they are permanently leaving behind their past lives and the security that the house represented, stepping into uncertainty and dispossession. The story's ending is significant as it speaks to the impermanence of material possessions and the human condition of adapting to loss and change.