Quick physics theory: there are thousands and thousands of other dimensions much like our own, each essentially “spun off” every time someone made a choice or went a different direction somehow. So these other dimensions in the multiverse can be very, very like ours or very different, depending on when those changes happened, when and how the “forks in the road” split off.
This idea is ripe for some great fiction. My favorite is the TV show “Fringe,” which explored scientists being able to enter some of those other different worlds. In A Thousand Pieces of You, Marguerite Caine is the daughter of two geniuses who have come up with a device that allows people to temporarily inhabit their alter egos in other dimensions. They haven’t even tested it yet, but then one of her parents’ grad students/assistants kills her father, destroys their work in the lab, and uses the device, the Firebird, to hop into one of the other dimensions. Marguerite and one of the other assistants (both of whom are like family to her and her parents) decide to use two other, older versions of the Firebird to chase the betrayer and hunt him down. She is determined to kill him and avenge her father.
The story takes them through several dimensions, which vary in how similar or different they are to Marguerite’s own reality, and the book often feels like the setup is just a gimmick to explore a few main characters in somewhat different settings. When some more of “the truth” comes out about who the real bad guy in the story is, the “gimmicky feel” lessens. But then the story also feels like it is just a way to explore a love story or triangle in different ways. At first, I was a bit skeptical and too aware of my feelings that it was a gimmick, but for much of the book I was then able to just get into the story and enjoy it as it was. Naturally, it’s not a stand-alone book, it’s at least part of a trilogy, which seems to be the automatic setting for YA books nowadays, so although that’s a bit annoying, I enjoyed this well enough that I’ll keep reading.
Rated: Moderate. There’s not much in the way of language, and not really much violence, though there is some peril and talk of potential murder, but there are some sexual scenes. Sex does happen in one scene, with a small amount of detail, and there are some other kissing scenes and references to the possibility of sex happening. The main character is right around 18 and the male love interests are young adults, a few years older.