This story is very hawt. But it's not *just* about the D/s aspect; it's about the romance between Dalton, Cade, and Erin. It's about three people's journey from "it's just sex" to "maybe it's more."
One evening, Erin walks in on a private moment between Dalton and Cade, and can't look away. Long story short, Dom Dalton and his sub Cade both want to add Erin to their relationship, such as it is, and teach the vanilla princess about the art of D/s.
But Dalton's been hurt before, and Erin's been hurt before. Can they get their poop in a group in time to realize what a great thing they've got going for them?
For those unaware of the significance, "D/s" means domination and submission; between the sheets, Dalton is in charge, and all three of them like it that way. This story does explore a variety of M/M, M/F/M, and M/F scenarios, so if light bondage and polyamory aren't your thing, I suggest you search elsewhere.
One thing I wished to see more of is the Dalton/Cade dynamic. I really wanted to see more of that intimacy -- and not just in bed. I wanted to see more of the relationship we missed out on before Erin waltzed in to join the party.
IMO, the middle section slows down a bit, getting bogged down by all the steam (ahem) which seems rather excessive, despite how extremely hawt it is. Toward the end, though, is where the relationship gets tested, and I kind of find myself wishing that maybe the relationship aspect took more precedence throughout, and yet I understand that the middling ground is necessary for the growth of each character individually and each character as a part of the trio. Silly critiques, really, but I can't really think of much else on which to comment.
If you like a good, steamy menage, I'd definitely recommend this book. Characters are solid, pacing is good (for the most part), and the ending (HEA) doesn't overstay its welcome.