This a fantastic opener, already has a Grimm fairytale feel, dark but classic, but my interest is already piqued because I want to know what this land down the well is. I can't wait to find out.
Also, the notion of going to "Wonderland" through the terrifying ordeal of drowning definitely has my darker, morbid side intrigued.
I love the haiku scattered throught, quite an interesting format. Must look into this haibun myself, it intrigues me.