Second in the Lighthorse series of books, "The Lighthorse League, Mystery of the Hidden Tunnel," finds Logan Lighthorse, Zack the Flak Johnson and Timothy Fox all together again. Having previously bullied Logan and Zack, Timothy has since resolved his issues and has now formed a tight bond and friendship with Logan and Zack. Ready to enter middle school, the three boys assume their lives are finally getting back to normal. But a girl named Mary Willey suddenly inserts herself into their lives, becoming a particularly disturbing nuisance to Logan. Even worse, after a hurricane has caused extensive damage to Mary's home, she and her mother move into the Lighthorse home while their house is being repaired. Logan is beside himself and tries every way imaginable to avoid her. But Mary is not to be deterred. A strong-willed and determined girl, she soon becomes a very big part of a quest to rescue someone very important to Logan. Mary unknowingly leads them into a world they never knew existed. A place where evil reigns on one side of this mysterious world and the ghost of Diwali Lighthorse reigns on the other. Trying desperately to get back home, Logan, Timothy, Zack and Mary will discover things about themselves and their family members that opens their eyes to a whole new understanding. And a bond will form between Logan and Mary that Logan never thought possible.