The Light Thieves And The Terrifying Dawn By Helena Duggan

People know that the sun is being stolen by tech-billionaire Howard Hansom, who’s been spinning everyone a massive lie. The only person who can stop him from plunging the world into darkness is the mysterious White Rose. She must keep her identity a secret, so she’s been sending out coded letters hoping good people will find them and work out what’s going on. Young heroes, Grian, Shelli and Jeffrey have been deciphering her letters and are close to solving all the puzzles. But they need one more set of clues to help them in their quest. Can they find the White Rose before it’s too late?