He took a vow to never love again. Then he bought himself a husband. When Jonah walks onto Vesper harbor at midnight to beg for his brother’s life, he expects to die. Instead, he kneels in blood at the feet of Cassian Varo, the cold king of the city’s docks, and makes a desperate trade. His freedom, for his brother’s heartbeat. His name, for a contract ring and a place at the mafia king’s side. To everyone else, Jonah is just a bargaining chip, a pretty hostage in a suit. To Cassian, he is a problem that feels too much like a second chance. As rivals circle and bodies drop, the “fake” marriage becomes a loaded weapon in every war room and every back alley. Jonah is soft heart and sharp tongue, furious at the world that made him kneel. Cassian is ruthless control and buried trauma, haunted by the lover he watched die on his harbor floor. Their days are negotiations and rules, their nights are shared nightmares that slowly turn into something more. Enemies become reluctant allies. Reluctant allies become forbidden desire. Desire turns into an obsession the city can see. But Vesper has long memories and no mercy. A leaked photo, a traitor close to home, and a kidnapping on the water drag old ghosts back into the light. To get Jonah back, Cassian must risk everything he has built, including the fear that keeps his crown in place. Jonah must decide if he can trust a bloody king who is finally choosing love over power, even as bullets hit the harbor he once hated. If Cassian bends, the empire might break. If he does not, the man he loves will die. Vesper King’s Vow is a dark gay MM mafia romance with a forced marriage, a morally gray mob boss, a soft but fierce husband, slow burn obsession, hurt and comfort, harbor wars, and a hard won HEA. Expect high tension, steamy on-page MM scenes with clear consent, emotional scars, found mercy in a brutal world, and a king who chooses his husband as his vow. Perfect for readers who Dark MM mafia romance Forced marriage and contract husbands Obsessive, possessive kings who never hurt their man Broken but healing together, trauma and comfort Dangerous cities, harbor wars, and a soft heart turning an empire Content violence, guns, kidnapping, past death of a partner, trauma and panic attacks, mafia politics, steamy MM romance, HEA.