A shadow is looming over the great hot southern land of Ashdod. It is the shadow of threshold, the pyramid that the Magi of Agi are building to propel them into Infinity. But something is waiting in Infinity. Waiting for the final glass to be laid, waiting for the capstone to be cemented in blood, waiting to use threshold to step from Infinity into Ashdod! thousands of slaves have been drafted into the construction of threshold. Among them is tirzah, a young glassworker. tirzah has a secret gift - and one that may kill her. She can communicate with glass, and what the glass of threshold screams at tirzah every time she touches it drives her to despair. Boaz, the Master Magus, is watching tirzah. He knows she's hiding something and he'll do whatever it takes to discover it. But what secret does Boaz hide? And why is the Song of the Frogs the only way to Save Ashdod? A shadow is looming over the great hot southern land of Ashdod. It is the shadow of threshold, the pyramid that the Magi of Agi are building to propel them into Infinity. But something is waiting in Infinity. Waiting for the final glass to be laid, waiting for the capstone to be cemented in blood, waiting to use threshold to step from Infinity into Ashdod! thousands of slaves have been drafted into the construction of threshold. Among them is tirzah, a young glassworker. tirzah has a secret gift - and one that may kill her. She can communicate with glass, and what the glass of threshold screams at tirzah every time she touches it drives her to despair. Boaz, the Master Magus, is watching tirzah. He knows she's hiding something and he'll do whatever it takes to discover it. But what secret does Boaz hide? And why is the Song of the Frogs the only way to Save Ashdod?