The Day You Arrived, Granny Could Tell
"Granny, we told y'all already." Apple Bloom said, "Ain't nopony s'posed ta visit t'day. They rarely do."
"Ah told you, whippersnapper," Granny Smith said, "They ain't comin' fer a visit!"
"Just who are they, Granny?" Big Mac asked.
"It was all in a letter from yer parents," Granny said, "Ah ain't s'posed ta show it to you."
"Granny, if it's from Ma and Pa, who disappeared years'go, Ah'd like ta see it." Apple Bloom said.
"Ah burned it, so y'all wouldn't read it." Granny crossed her forehoofs and looked away.
"Granny!" Big Mac said, and then there was a knock on the door.
"It's them!" Granny screamed, and rushed to the door. She returned carrying a young filly, still a baby. She was wrapped in a blanket. Her fur was green, and her mane was blonde, just like Applejack's. She slept, almost too peacefully.
"Granny, where did that foal come from?!" Apple Bloom asked.
"Apple Bloom!" Granny Smith yelled, "This here foal is yer sister!"
"B-but how?" Big Mac asked, "Ain't our parents-"
"Yer parents had ta leave," Granny smiled, "But that don't mean they abandoned you. An' look, they still had time ta give us this here cutie!" Granny hugged the foal.
Apple Bloom sat next to her grandmother. "What's her name, Granny?" she asked.
"Abelle." Granny said. Big Mac looked over her shoulder.
"Abelle Apple."