The Ghost Gang of Mortimer Mountain

This story is about teen cousins. One set of cousins twin teen boys 15, younger brother 13 and an older sister 17. From the west coast.  The second set of cousins, Twin boys 13, a sister 16, from the east coast.  Meet for the first time in seven years on a summer vacation to a ghost town resort with family members to meet a distant 7th cousin 84, owner of the ghost town hotel resort.  The cousins discover a secret, a riddle to solve, and learn there is a kidnapped teen in the ghost town held by his two men for the last six months.  We have a rescue of the teen boy 16, an FBI shoot out one captive dead, an FBI agent wounded.  Now 8 teens looking for treasure risking life to solving clues.  An FBI and Interpol sting, International diplomates, Presidential visits.  Teen romance, school bully's, Hate crimes, crooks everywhere you look.  Lies, Truth, Family drama, humor, acceptance and interventions.  Oh, I forgot, a gang of Ghosts in the Ghost town of Mortimer Mountain?