Raubritter*

Three years ago, Neneko lost her father and has since lived with her older sister, Nanako. Their peaceful life changes when Nanako begins behaving oddly, skipping nights at home and eventually vanishing. She also abruptly quits her long-term job. Concerned, Neneko visits a place her father mentioned for emergencies—the Raubritter. There, she meets Shinobu and Yokana, cousins who run a detective agency as a hobby. They are wealthy and offer free help to those in need, keeping their services discreet. Their clientele consists of those with prior connections, and Neneko's father had aided them in the past. Learning of his death, the cousins are upset and agree to assist her in finding her sister.