The protagonist, Kouma Akebonoin, is a barista working at a cafe on Minoba Island, a large resort area.

There were rumors of strange drugs being traded on the tropical Minoba Island recently, but he didn't pay much attention to them. Around the time the rumors started, three tourists visited the island at the invitation of the island's owner.

One is Mihiro Utatsugu, a cheerful college student who exudes a lively and outgoing aura. One is Rina Ogawa Komado, a young female teacher who seems to be a well-bred lady. And Hazuki Mameruri, a female doctor who transferred from the mainland at the request of the island's clinic.

For some reason, all three become close to the protagonist and develop deep, intimate relationships. That was because each of the three... no, four of them had secrets.

Set in a tropical resort, a top-secret paradise story unfolds with the protagonist and three busty swimsuit heroines revolving around drugs and secrets!