After being selected as an advertising model for a high-end lipstick brand, the wildly popular model Kakan receives death threats. To create more buzz, her agency takes out 300 million yen insurance on just Kakan's lips, and also decides to have a bodyguard by her side 24 hours a day. The bodyguard who arrives, Rion, is a straight-laced man who shows no interest in Kakan, and Kakan feels resentment towards him...
"If I lose control, I might damage your lips and mouth..."
(Source: Kadokawa, translated)
— Description from AniList community (anilist.co).
