What if every promise you spoke kept your city alive... and one broken vow could burn it to ash?High above the Ash-Wastes, the city of Heliovers drifts on sails of glass and song. Its lifeblood is solarday - a fragile light woven from vows spoken in harmony. For generations, great festivals kept the spire blazing. But now, every forced chorus collapses into blackout, leaving the city weaker with each celebration.Kael, an engineer who trusts equations more than people, discovers a dangerous pattern: only the small, uncoerced circles endure. Mira, a defiant chorist, refuses to sing a single note that isn't freely given. Together, they uncover a truth the Council cannot afford to face - the shards remember every vow ever spoken... and some of them are starting to wake.As skylash storms batter the sails and politicians turn truth into spectacle, Kael and Mira are drawn into the Trial of Truth - where the cost of failure is not exile or disgrace, but the fall of Heliovers itself.Solarday of Ash & Ember is the first book in The Vowlight Cycle - a sweeping epic of vows and resonance, where truth is power, glass remembers, and the smallest promise can change the fate of a world.