Red Moon and Black Mountain is the first volume in Joy Chant’s House of Kendreth trilogy.
Siblings Oliver, Penny, and Nicholas Powell set out to explore Essex. Thanks to the intervention of an arcane being, the trio are transported from England to Vandarei. Vandarei needs heroes of a very special sort and English school children have the necessary qualifications.
Penny and Nicholas arrive together but Oliver, somewhat in the lead of his younger siblings, arrives somewhere else entirely.