18+ Yakuza to Hanabira

Saki Ogawa lives a similar life to the flowers she tends to: she wakes up in the morning, is active while the sun is out, then goes to sleep at night to repeat it all the next day. So when she goes to a nightclub for a delivery, Saki enters a new world full of allure and mystique. The nightclub owner Renji Kanamori is just that: alluring and mysterious. Saki can only imagine all of the shady business he must conduct. At least she won't have anything to do with him...!

(Source: Fantasista Inc.)

Included one-shots:
Volume 1: 3 x P x Fighter! (The Triangle Fighter)
Volume 2: Torotoro Summer! (Melty Summer), Oyoshi ni Natte Goshujinsama! (Please Stop! My Master)
Volume 3: Center of the Earth
Volume 4: Upgrade