The latest Troubletwisters novel is undeniably the best so far - The Mystery of the Golden Card focusses on Jaide and Jack's first Warden-related mission and gives readers a lot more action than ever before. I like the development of the characters in this book, both the adults and the children, and it feels like the series is finally going somewhere.I really like that the secrets hinted at in the previous two books are finally coming to light. The twins are better at connecting the dots and figuring things out in this book. The best part is definitely their reluctance to accuse any of their acquaintances as spies for The Evil, they have certainly come a long way from the previous book, where Jaide was accusing innocent people of working for the enemy without a shred of proof.I also liked the plot and the nice twists and turns that kept the story hurtling along. I found it slightly predictable (but remember, the book isn't aimed at people my age), but I think the plot makes sense and is handled well. The Mystery of the Golden Card definitely feels more polished and smoother than the two previous instalments.I was, however, uncomfortable with the secrets that the twins ended up keeping from the adults around them: they hid important things from their grandmother and their parents in the hopes of solving the mystery before anyone knew something was wrong. The worst part: they were actively encouraged to do this by a member of their family. It all worked out in the end and I now know why it had to happen that way, but while reading I was increasingly uncomfortable with the whole situation. I did like that the twins were told the importance of never hiding things from those responsible for their safety and well-being, and so I'm hopeful that this will be less of an issue in the future.The expansion of the world and the magic the Wardens use is great to see - I loved the cool devices Jack and Jaide used to find the missing card, and the talking death mask of a Warden from ye olde times is my new favourite character. In addition to the magical elements, I loved the introduction of a few new characters, including Cordelia, a talking bird who I adored. I hope she continues to make appearances in the series.Fans of the Troubletwisters series are encouraged to read the newest offering, The Mystery of the Golden Card. It's a thrilling adventure that has just the right amount of monsters, action and heroes. I feel like the authors are hitting their stride with the series, and have high hopes for the future.A copy of this book was provided by the publisher for review.You can read more of my reviews at Speculating on SpecFic.