Chelsea Cain's first thriller, Heartsick, was an interesting debut with a fascinating protagonist in fragile homicide detective Archie Sheridan. Cain's latest book, Sweetheart, continues Archie's story and dysfunctional relationship with his arch-nemesis, Gretchen Lowell. In addition, threads that were left hanging in the first book are resolved, some rather messily. Cain leaves things open for a third book, which may be pushing things, but at the moment I have to say I greatly enjoyed Sweetheart, though perhaps not as much as the first book.

Archie Sheridan is trying to rekindle his relationship with his ex-wife and kids, though his attachment to Lowell continues to stand between them. Meanwhile, reporter Susan Ward is continuing her quest to bring down an Oregon politician for a sex scandal many years before, information for which is just coming to light. This investigation seemingly takes a back seat when Lowell escapes from prison and begins to terrorize both the Sheridans and the Wards (Susan's mother is along for the ride). Archie hatches a mad plan to finally rid both himself and the world of Lowell's psychosis, but he may be digging himself in too deep to ever get out. Perhaps that's the whole point?

I really do like Cain's character work, though some of the characters' mannerisms were starting to grate on my nerves as they kept coming up. Too many chapters or scenes begin with Archie carefully contemplating the numerous Vicodin pills he's taken out of their container, for example. I'm not saying this is unrealistic - I'm sure this isn't unusual for recovering addicts - but dramatically it’s annoying after a while.

Still, I had trouble putting Sweetheart down as Cain's characterization and prose kept me glued to the book. The book moves very quickly from one situation to the next, but that doesn't keep Cain’s characters from getting introspective. Most of the time it's interesting stuff, though again it drags on a bit. These were the times where I was able to break away from the book and go to sleep.

The interaction between Gretchen and Archie gets to be delicious after a while, with Lowell's mind games taking Archie deeper and deeper into the abyss even as Archie himself is works to bring Gretchen down with him. He can't bring himself to treat her normally: in his mind, ridding the world of Gretchen Lowell has to result in his own self-immolation as well. The novel’s climax is riveting, even if getting there seems to take a while (when there's a mad dash to rescue the protagonist of the story, the mad dash part shouldn't really take so long, should it?). The final confrontation had me on the edge of my seat.

A few problems that weren't in the first book crop up in Sweetheart. While the Gretchen/Archie plot isn’t definitively ended, pretty much everything else is, and the conclusion to at least one of the stories seems too convenient. Susan finally gets to the bottom of her political scandal, and that ending is unsatisfying, seeming to come out of left field (not the identity of the bad guy, necessarily, but the final result of his/her discovery).

Secondly, Susan's mother’s New Age attitude toward her daughter, her naked yoga, and her flighty personality all made me wish Cain was doing something else with her. She isn't in the first book much, but she takes a bit more of a central role her (not too much, but enough) and thus becomes more irritating.

One warning for sensitive readers: There is some explicit sex in this novel, unlike the first one where it's more implied. There's also the staple of this genre, gore, though not nearly as bad as in the first book.

Sweetheart, while not equal to the first book, is definitely worth a read if you're into the serial killer/thriller genre. It won't tax your brain, but it will entertain you. I just hope Cain doesn't keep this series up too much longer without introducing something fresh. Something's got to give at some point, and Gretchen Lowell can only keep the series centered for so long before Archie ceases to be interesting.