There are 4 books in the Mirror Visitor Quartet series.
The Mirror Visitor Quartet series does not have a new book coming out soon. The latest book, The Storm of Echoes (Book 4), was published in October 2021.
The first book in the Mirror Visitor Quartet series, A Winter's Promise, was published in September 2018.
The Mirror Visitor Quartet series primarily falls into the Fantasy genre. This young adult series was written for ages 12-17, but can be enjoyed by adults too.