I have just begun to read The Juniper Tree by Barbara Comyns. This is adapted from a Grimm tale and makes a wonderful, absorbing story. She has taken the characters and plot from the original and made it her own. However, the setting is different. The atmosphere and tension and pace are her own creation too. It is menacing and macabre. I love it.
There is nothing wrong with using a plot that has already worked well for another writer. I noticed a winning story in a magazine competition, which was very similar to one of my own, a previous winner in the same publication. But I didn't mind. I was flattered. The new story was still the author's work, his style, his choice of vocabulary. He had been inspired by mine, rather than merely copying it. Without doubt, I had been inspired in a similar way when I wrote my story. In fact, I remember well the novel which planted the first seeds.
We all grow our own ideas from ground cultivated by others. But, as long as we choose to use our own voice, the new work of fiction we create will be fresh and unique.