Okay, time for a proper review.
One Was Lost follows Sera as she and three others - Jude, Lucas, and Emma - are stranded in the woods on a school campout. When they wake up with cryptic words written on their arms and their supplies shredded, it's made clear someone is following them and wants them dead. What was supposed to be a simple backpacking trip soon turns into a fight for survival with a lot of teen angst.
Overall it was a fun book. There was suspense and I enjoyed trying to unravel the mystery. There were a lot of parts where I didn't want to stop reading due to how intense parts of it were, such as with the bears. Sera was a good main character and I liked watching her react to things. In particular, she felt real in her reactions. Like, freaking out when she sees a finger? That's totally what a normal person would do and I like that Richards went for making her normal rather than trying to make her this steely badass like some other writers might.
The biggest flaw to the book is it felt very drawn out. Like, when you actually look at the events, not much actually happens. Most of the book is either the teens arguing or Sera dealing with her sexual frustration over Lucas. By the time I finished the book, I realized just how hollow the story really was.
Similarly, while the mystery wasn't horribly constructed, it wasn't developed as much as it should have been. The identity of the bad guy wasn't totally out of left field but the method they were employing didn't make as much sense. It reads like Richards knew who she wanted her antagonist to be and just thought we could put it all together. The problem with this is we didn't get to know the antagonist well enough to recognize the significance of all the events. They can be linked together, it's just by a very feeble thread.
Final rating: 3.5 out of 5 stars. It's a cotton candy read and really more about Sera's relationship with Lucas than an actual mystery. But if you go in knowing that and your expectations are appropriately adjusted, I think you'll enjoy it.