Cruise Adventure Arc

Yor is hired to protect a mafia heiress and her son aboard the Princess Lorelei from a swarm of assassins, while Loid and Anya coincidentally board the same cruise, pushing Yor to question her assassin life.

The Cruise Adventure Arc, known in the anime as the Luxury Cruise Ship Arc, follows Yor on a major solo assignment from the assassin organization Garden. Through the Shopkeeper, Yor, as Thorn Princess, is hired to protect Olka Gretcher and her young son Gram, the last survivors of a fallen mafia family, as they flee Ostania by sea aboard the Princess Lorelei. The new crime boss has placed an enormous bounty on the pair, drawing hordes of assassins onto the ship. Complications mount when Loid and Anya coincidentally win tickets and board the same cruise, forcing Yor to guard her clients while concealing her work from her family. As wave after wave of killers attack during masquerade balls, fireworks shows, and bomb plots, Yor fights to fulfill her contract, aided unknowingly by Anya, who uses her telepathy to help, and by Loid, who quietly defuses bombs planted by an informant named Snoops seeking to provoke war. Throughout the mission, Yor wrestles with deep doubts about whether to continue her dangerous assassin life now that she has a family. Reaffirming that she became an assassin to protect those she loves, she succeeds in delivering Olka and Gram to safety, and the family reunites for a peaceful day on a resort island.