The heat of the summer is just beginning when my younger sister calls me to celebrate my divorce. My ex wasn’t horrible; we just fell out of love. It just took a few years to realize it. I’m alone and unprepared to dip my toe in the dating pool. I’m fine—really, everything is fine.

My sister Holly is a stewardess on a posh luxury sailboat hosting über-rich billionaires in the Caribbean. It’s sweet that she calls, but she seems so busy. When she forgets to end the FaceTime call, I see what she’s been doing—namely her stewardess crew mate. After that eye-opening and core-clenching revelation, Holly calls back with more news.

She’s bought me a ticket on a sister ship for a two-week cruise along the Yucatan peninsula. Her boyfriend, the nameless captain of her ship, paid for all expenses. It sounds fun and includes a five-day stay on a private island for a “freeuse excursion.” I’m not sure what that means, but Holly thinks it’ll be just what I need to break the ice on my sexless existence.

My temperature rises when I start researching what freeuse means. It’s some BDSM thing. It’s not the whips and chains type, but a type of dominance submission game between consenting adults. It’s completely foreign to me, but I’m tired of being alone, and the idea of a hedonistic vacation sounds incredible.

What the hell? Right? Little sisters always seem to have the most fun. Why can’t older sisters bend the rules, too?