Sanarara

It was something that could happen to anyone — a tale with a tinge of mystery... One day, a girl I didn't know approached me; she told me she would make true any wish I desired — but only one. "Really?" I thought to myself. She didn't exactly look dependable. She started explaining how it would work as I listened on in disbelief. "Let's see, according to the manual..." 1. Once and but once in your life, one wish shall be granted. 2. This opportunity will be given to all who live in this world. 3. One cannot know when it will be offered ahead of time. 4. The one notifying you of the opportunity shall be known as the Navigator; until the wish is fulfilled, they shall not be freed from their position. 5. The Recipient of the Navigator's aid shall later become another's Navigator. 6. Once their duty is complete, the Navigator shall lose all memory of the event. [or both, unclear] (1). When a Navigator, you are as insubstantial as mist to anyone but the Recipient. (2). You will not be able to tell anyone else of this. (3). If a wish is deemed obviously impossible to grant, it may be disregarded; be careful. (4). You must decide what to wish for within one week. Well, that was certainly an explanation. I wasn't about to believe her based on her testimony alone, but she did strike me as... subtly different, in some way. [Translated from Getchu]