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A Knight In Camelot was adapted into a film starring Whoopi Goldberg. She is a scientist that activates a time travel machine.
She is flown into the past with some of her office supplies. This includes a laptop computer, cell phone, and boom box. She is able to determine the next eclipse and it is able to save her life and earns her royalty as a knight and sorcerer. She is given three servants and she recruits two more. She demands cooked vegetables and "invents" dynamite and steam power.
Somehow the batteries in her devices remain charged at all times.
It is a great film but the ending makes no sense. She should NEVER invent the time travel machine without a way to bring her back to her home time. And she should have lived out her life in the past, "inventing" things, and perhaps starting a family, which she would meet her own descendants once she flies herself to the future.
Instead, Merlin is another scientist that discovers her time machine, brings her home, and he says none of them will remember her. And then they walk... LITERALLY walk, into space.
So much more could have been done instead of an ending that is actually WORSE than the "It was only just a dream." concept.