Runaway

Betty is being terrorized by the black hood, calls, constant threats and on top of that her parents have been fighting.
One night she receives a call from him telling her she has to leave town without a trace...but she can't tell anyone, because he will always know.
She leaves, Riverdale goes into full panic when they find out about her sudden disappearance.
The final conclusion after a week was that she was dead, people saying she may have been murdered, or even done it to herself.
After three years, When Betty's face had faded from everyone's mind and they only had pictures to remind them of her, and even then, that wasn't enough.
Then, suddenly Senior year, a girl with short brown hair and blue eyes show up in the main office and something seems oddly familiar.