From Clamp no Lumiere:
Hanato Kobato is a cute girl who has a mission: fill up a mysterious bottle she carries with her in order to grant her wish. For that mission, she's counting with Ioryogi's help, a little blue dog who seems very cute but who has a terrible foul mouth and bad manners. Now, Kobato-chan has to heal the people whose hearts are wounded. The only problem is that she doesn't really know how to do it. The more people/hearts she heals, the more her bottle fills itself. She only needs to take care to not fall in love with the person she's healing.
For what purpose Kobato needs to fill that bottle? Who sent her for this mission? Will she succeed?