The Secret of the Night Train by Sylvia Bishop
Although Max loves her family and their quiet life in Paris, she longs for adventure so that she can fill her notebook with all the excitement and daring twists and turns - so when her great-aunt Elodie calls and insists on having someone to stay for the holidays, Max jumps at the chance of travelling to Istanbul.
Accompanied by (the slightly exuberant) Sister Marguerite, Max's adventure begins even before they have left Paris, when the train is searched for the missing Heartbreak Diamond - an extremely rare diamond that was stolen from the bank earlier that week - inspiring Max to begin her own investigation into her fellow passengers.
As her list of suspects narrows with each leg of her journey, soon Max is faced with a handful of names, as well as quickly discovering an unlikely ally in her detective work. Faced with the realisation of quite how deep she is into this dangerous world, Max must unravel the mystery as quickly as she can. Will she manage to find the thief and bring them to justice? Or will she find herself in a situation she can't get out of...?
Perfect for fans of Cogheart, and Brightstorm, or those looking for a mystery-filled adventure, Sylvia Bishop's first junior novel is as quirky and fun as readers have come to expect from her, and also is an absolute joy to read aloud. With the stunning cover illustration by Marco Guadalupi, this book is every bit as much of a treat as it looks.