A secret call for help sends Jack Coughlin, his brother, Collin, and Collin's friend, Danny, back to The Hidden Moon to save their new friends!The Hidden Moon adventures continue when twelve-year-old Jack Coughlin awakes to find the stone on his bedroom dresser glowing green. It's not just any stone, it's a special stone given to him when he, his younger brother, Collin, and their friend, Danny, magically visited Anron, The Hidden Moon. The stone is flashing a signal: dit-dit-dit, dah-dah-dah, dit-dit-dit: S-O-S in Morse Code. It can only mean one thing, their new Anronite friends, Karna and Nidar, need their help. The boys once again magically return to The Hidden Moon to discover Karna's father, Minron, the head of the People of Light, has been declared missing after being assigned the role of King on nearby Planet IXX. They discover Minron's twin brother, Ronmin, had been tricked by the evil Grun into thinking Minron should be dethroned, not knowing Grun is doing this so he, himself, can take over as and destroy the People of Light. Jack makes a secret mission to Planet IX to inform the twins what Grun is doing, and then he, the other boys, and their new friends are caught in a dragon-filled battle to get rid of Grun. Another exciting fun fantasy adventure for middle-grade boys and girls! Be sure to read the other books in the series: Return to the Hidden Moon, and Trouble on the Hidden Moon, where more adventures await the boys and their two new moon friends, Nidar and Karna.