Yor receives a high-priority, bloody assignment from her shadowy assassin organization, Garden, forcing her to step back into her role as the Thorn Princess. Her mission is to board a luxury cruise liner called the Princess Lorelei to protect a wealthy mob informant and her young child from an absolute army of highly trained, ruthless assassins. Coincidentally, Loid wins vacation tickets to the exact same cruise ship through a lottery, bringing Anya and Bond along for a family trip. Yor is forced to engage in a series of brutal, exhausting skirmishes in the ship's shadows to keep her clients safe, all while desperately trying to hide her blood-stained clothes and injuries from a vacationing Loid and a telepathic Anya.