The stakes are much higher in the sequel to The Ruby Key and Lisle complicates matters much more when she reveals that the good guys may not have been as good as they were thought to be. The Silver Door is a well thought out novel that ups the ante in the Moon and Sun series as Genna and Catri find themselves stranded in the castle/estate that belonged to the human civilization of yester years. Secrets are revealed and some friendships are forged anew while others sacrificed. There are hearts broken and hearts that skip a beat for the first time. The tension between Doyati and Genna are, at times, infuriating and at times endearing. Genna’s role in what appears to be fast becoming a war for survival is further fleshed out and the reader gets a premonition that much may be expected from Genna, perhaps more than she is willing to give. The novel also presents an interesting question – one of human fallibility. Whether we, as a race, have the strength to continue even when we have been displaced from the top of the food chain. All in all, The Silver Door is just as riveting a read as The Ruby Key and I recommend anyone who’s looking for a strong, kickass heroine with an intriguing love interest and a brother who is just as dashing as she is to read this book. You will be entertained, you will laugh, cry, gasp and at the end, thirst for more.