CC-0 derived work can it be locked by copyright?

Question

Let's say someone released something, a detailed scene of a story, as a CC-0 work.

An author took that work, expanded on it (the work became a part of the story), and protected their complete work under copyright.

Then one day, I myself had an idea -- in whole, totally different from the aforementioned author's -- and I use that detailed scene as well in my work.

Can I get into hot water for basing the idea on the same CC-0 work?

And what if the original CC-0 work was actually my idea, and I can prove I'm the first one to release the work, can that protect me?

Answer 1

CC0 means "free to use for everyone", not just "free to use for the first one who finds it".

If a work is based solely on the CC-0 source and does not infringe on anything other authors added in addition to the CC-0 source material then those authors have no claim on the new work.

But that does of course not protect you from getting sued in the first place. The other author might claim that they have never heard of the CC-0 source and that you stole the basic idea from them. Now you need to prove that your story is based on the CC-0 material, not on the other authors interpretation. That's a lawsuit you might win in the end, but only if you are willing to invest money into it.