A remote island hotel's grand reopening descends into tragedy when a treacherous tide claims several guests, leaving the organizer trapped with a growing fear and the suspicion that someone knows the dark truth. Hannah, the organizer of The Stanhope hotel's reopening, watches with pride as wealthy guests arrive. However, the celebration turns to horror when drunken revellers enter the water during the treacherous tide known as The Drowning Hour and disappear. Tormented by a phobia of water and stranded on the island over winter, Hannah becomes increasingly fearful as whispers about the night's events circulate, suggesting someone knows what truly happened and that she is in danger.

The Drowning Hour is positioned as an unputdownable psychological thriller, appealing to fans of authors like C.J. Tudor and Ruth Ware. Its premise suggests a tightly plotted mystery with a strong sense of atmosphere and suspense, focusing on the psychological impact of a tragic event on the protagonist. The narrative is expected to deliver twists and turns, keeping readers guessing about the true events of 'The Drowning Hour' and the safety of the main character. The setting on a remote island further enhances the claustrophobic and tense nature of the unfolding mystery.