Sissy and her stepbrother, Dustin, are both in college now and their parents are finally letting them plan a trip to the family's cabin on their own. But when it turns out that Sissy's sometimes-boyfriend bails on her for the umpteenth time, and Dustin's on-again off-again girlfriend gets sick and can't go, the siblings end up precariously alone. This gives both of them an opportunity to reveal some taboo truths and forbidden fantasies they've kept secret from each other. For Sissy and Dustin, things are about to get real.

Sheltered Cassie is off to college and experiencing freedom for the first time ever. Her stepbrother, Xavian, has been enlisted to keep an eye on her. They're going to room together, after all, in a little apartment off-campus. Xavian's even booted out his old roommate, Joel, so Cassie will have her own room. When Xavian discovers Cassie starting to spread her wings in a brief encounter with Joel, he goes off the rails in a jealous rage, forcing Joel out of the apartment to protect his innocent stepsister.

Innocent Allie's been saving herself for the right guy. The problem is, the right guy just happens to be her sexy, older stepbrother, Kit. Kit is funny, sweet, hot, has a panty-melting English accent - and he's completely off-limits. When everyone else abandons Allie on moving day, Kit is there to pick up the boxes - and the pieces of her heart. Deep down, she knows she wants her first time to be with her stepbrother, and when things finally go too far, neither of them can stop their overwhelming, unprotected need to be together.

Winnie spent years in law school and has been living on a law clerk's meager salary - the only job she could find - while her older stepbrother, Upton, makes six-figures a year writing trashy romance novels under a female pen name for the masses. Not that she begrudges him - they might be step-siblings but they've always been more like best friends. Upton considers Winnie his muse, so when he calls with terrible writer's block, desperately begging her to come up to the summer house where he's trying to meet his deadline, Winnie relents.

Bailey's graduate science classes are much harder than she expected them to be, and strict, young Professor Jacobs, in particular, seems out to get her, finding minute mistakes in her work, making her re-do assignments she's already meticulously completed. When he forces her to start staying late in the lab, Bailey complains to her roommate that she's about ready to quit school altogether, but what she doesn't know is that her stern professor has a carnal lesson he's waiting to teach her.