The Small Heart quest is one of the essential quests in being an Aisling. It starts with Marlin in the Loures Caslte, where he will tell you of his lost love, Bella. You must find all the clues, and return to Marlin, where you will be sent to the underground of Loures to preform the Heart ritual. By yourself, you may preform the Heart of Stone, and be able to enter the maze at any time you wish, or the Heart of Fire/Moon with a partner, and be able to cast Dia Naomh Aite on yourself in Loures Dungeon.