Broken Devil

He dumped her on their wedding day, giving her an excuse that he wasn't ready to settle down and take life seriously but she later saw him making out with a girl on their favourite spot. She was so broken that she chose to commit suicide. She died on the very night their reception was to take place.
She left a suicide not which read "I'll be back."
Lucia's parents were devastated and blamed Luke for her death.

Luke surely felt guilty for a while but he later moved on with his life.

But what happens when they all forget what happened especially Luke?

Is Lucia really coming back? And for what reason?
No one took the note into consideration and ignored it but they had no simplest idea it is what it is.