The Good Ship Murder follows Jack Grayling (Shayne Ward), a former police detective who has left his law enforcement career to pursue his passion for singing as a cabaret performer on a luxury Mediterranean cruise ship. However, his tranquil new life is disrupted when murders begin occurring on board. Teaming up with First Officer Kate Woods, a determined and ambitious officer with much to prove in a male-dominated environment, Jack finds himself drawn back into investigative work. Together, they navigate the ship's glamorous yet complex social environment-marked by hidden jealousies, rivalries, and secrets-to solve a series of murders, each set against the backdrop of different picturesque ports of call, including La Rochelle, Lisbon, Casablanca, Palma, Sicily, Barcelona, and Malta. Each episode presents a new mystery, blending the allure of cruise ship life with intriguing whodunits, and concludes with Jack delivering a musical performance in the ship's cabaret lounge.