Crimson Waves on the Emerald Sea: Amaranthine Moon is the otome standalone sequel to Crimson Waves on the Emerald Sea, a Victorian vampire visual novel previously released in 2021. This visual novel is set around 5-6 years after the events of the first visual novel, following Lucie as the main character now that she's an adult.

Determined to make her own destiny as she turns 18, the young head of her family Lucie plunges headfirst in the conniving world of business dealings. Before she's able to seal the deal on a revolutionary treatment to vampirism, her business partner suddenly dies. Lucie finds herself embroiled in the middle of the mysterious death of her former partner and an event from a decade prior...