In the aftermath of the smoke bombs at the Hope Springs Grand Depot, Jay and his newfound friend Brace – along with school friends Dante and Woodward – suspect Zach was behind the trouble. Dante’s mother, Detective Rose Hall, arrives to investigate the crime – and learns that it may have been more than a mere prank. In the Depot’s restored Telegraph Office, Jay and Brace meet Andrew Perry, nephew of Clark and an amateur historian, just as mysterious and urgent messages come in on the old telegraph machine – which isn’t supposed to work!