Doorway to Nowhere is a delightful prequel novella to the Shadow and the Scream, detailing Annie and Sheb's tragic and traumatic histories. You're thrown right into the deep end from the start, and it's a dark and fast paced adventure. It's a creative journey of two strangers becoming friends, managing trauma and anger, and how they survived and adapted to their new world with each other and the quirky creatures that surround them.
The world building is creative and the story is dark, but it's an excellent tale and helps set the mood for the rest of the series, or can be read a short standalone adventure.