It's a gruesome tale of a serial rapist and murderer's victims. They call him The Gardener, and he personally tattoos a specific butterfly across each new girl's back that he kidnaps to keep in his "garden". If they go insane, become pregnant, or turn 21, he kills them, and often displays them in a case so that he can forever remember their beauty. 
 Yeah, there's a lot of gag-worthy parts, but not because the writing is poor, the opposite, rather. It's horrific what happens to these girls. The story unfolds in a police station, where the police are holding the major player of the crime after, presumably, rescuing the victims. The breaks in the story alternate between Maya/Inara at present, sitting in a questioning room, speaking with a special FBI investigator, and her time in The Garden. 
 The writing is compelling, and I was sucked into Inara's story, and all the characters, and enjoyed the whole experience, though certainly there were plenty of disturbing parts. I was not a fan of (view spoiler)[ the ending. I didn't like that Sophia had been in the Garden before, and actually escaped, only to NOT TELL ANYONE. Really???? Not right, Sophia. And then apparently that is why Maya was able to deal with the whole situation better than many of the others? Bleh. I would've preferred a different conclusion, but maybe this helps set up a sequel for The Collectors Trilogy. (hide spoiler)]