Maple is around 12 or 13 when this happens, but a mysterious dark storm has invaded her home, and while the other villagers are in hiding, Maple insists that she stays with her closest teacher, Yen Sid, to fight the storm, regardless if she's not quite ready to take on such a large threat, or something of this scale. With the dark winds swirling around them, Yen Sid has no way to send the child ruler back, and he keeps her behind him as he uses his magic to keep the storm's advances at bay. There is no way out for them.
However, out of nowhere, Maleficent in her dragon form swoops down and snatches Maple out of the fray, since (as she would recount later), Maple's foolhardiness in trying to fight the storm was too painful for her to just sit and watch. Little Maple protests this loudly and tearfully as she watches her teacher grow smaller and smaller the further Maleficent flies.
The two of them land on a nearby floating island, but the Mistress has to prevent the child ruler from trying to get back to Yen Sid inside the storm! Yen Sid watches this from afar, and with one final command and a satisfied smile in Maple's direction, he faces the storm...on his own.
The loss will remain with Maple for the rest of her days...even after the Forgetting, as Yen Sid was her first--and closest--teacher in the Valley.