Fiction Fridays: Elin Hilderbrand's Nantucket Nights

I love Elin Hilderbrand, but this novel fell a little short for me. I think because of the plot device of having one of the best friends disappear and the whole novel we were left high and dry. Was she dead? Was she alive? Pregnant? What the hell was going on? It felt too manipulative. I think that perhaps having us, the readers, in on it may have been effective but maybe not.
I understand why Hilderbrand did it. Keeping that carrot dangling definitely keeps the pages turning. But it just felt too forced to me. And I thought some of the decisions that the characters made were just too far-fetched. In her other books, every decision felt real and felt like something I might actually decide for myself, good and bad. But in this book, I just couldn't get on board with the decisions and lacked empathy for the maybe drowned/maybe dead character.
I think too that I hated to see three 20-year friendships shattered by selfish behavior. I know that in Hilderbrand novels relationships are going to be destroyed, but I just didn't get invested enough in the lives of these three women to care enough.
I want to read another Hilderbrand novel ASAP though. Any suggestions? I've read The Castaways and The Island so far.