The Sword and the Grail — Cynthia Roepke

A Young Adult Short Story -

Legend has it that King Arthur and his knights of the Round Table simply lie in sleep, waiting to be awakened to unify the world once more.

On the night of St. John's Eve, 1,464 years since she'd had last seen Arthur, Nimue had finally escaped from the tree in which Merlin had imbedded year so long ago. Tonight, when Arthur and his knights made their ghostly ride from Cadbury Tor, she could make them mortals once again -- mortals who would save the world from its self-destruction. All she had to do was get the spell right.

One person she wouldn't be bringing back was Gwenevere. The woman had been too much trouble the last time

Nope. This time, in the twenty-first century, Nimue would make certain no one interfered. Arthur would finally be hers.