does anyone know of this?
K. Pelle, aka dotB is the author. This is the name of the series of which Beyond the Mirror is one book. More info in author's blog.
The series to date, as I understand it: -
1 Jack's Journal Ch 1-6
2 Beyond the Mirror Ch 1-32 (complete)
3 Fifth Wheel Ch 1-5
4 Tit for Tat Ch 1-3
5 Dolda Hem 1-9