Mata Korosarete Shimatta no desu ne, Tantei-sama

Sakuya Otsuki, son of a famous detective, partners with his assistant Lilithea as he pursues a career in solving mysteries. Despite his efforts, he repeatedly ends up as the victim in the cases he investigates. Assigned to a luxury cruise ship for an infiltration mission, he is killed once more. Each time he awakens, Lilithea is present, assisting him in uncovering the truth behind the circumstances of his death.