Harry ends up in the past in his 6th year, founders time. He spends years there and eventually falls in love with Rowena, they have a kid. They name her Helena.
Something happens and Harry gets pulled into the present, and awakens moments after he got sent to the past.
He realizes something and immediately runs off in search of the grey lady.
He finds her, and she turns to see him crying.
"You remember?" Her voice hitches as ghostly tears wet her eyes. "Papa?"
Harry, unable to speak, nods.