After suffering a severe incapacitating anxiety attack on one of her quests, Daring Do runs away to be in solitude. The jungle safeguards her and lull's her into a trance. But the trance is broken when Daring realizes that if she does not leave, she will die and be forgotten, like dead leaves blown away in the wind.
(Although this is not really a "dark story" per-say, the themes addressed in it are on the mature side.)