Sukepan deka: Bâjin nêmu = Moromie Saki (2006)

She has no choice. She has to cooperate with the cops and be their undercover agent. The cops have her mother and the only way they will relent is if the daughter cooperates. She goes undercover to break up a schoolgirl prostitution ring armed with standard-issue see-through panties. She is duly kidnapped and taken to the lair where other girls are tied up and imprisoned. Thankfully she deploys her panties and the yo yo.