She's part of a program called Revive. It's a top secret drug that can bring people back to life. Only 21 kids get to use it (Daisy included). It's controlled by an anonymous guy they call God. The secret project and its sinister goal, in my opinion, was not investigated enough. We should have had a chance to learn more about it. It was a bit vague. But, it did have an entertaining plot, even though it wasn't very unpredictable.
Daisy has a very relatable voice, we can see her developing a relationship with Audrey and Matt, her first best friend and boyfriend. Being able to come back to life whenever she dies, Daisy doesn't have particularly strong feelings about death. So when she's faced with actual, non-reversable death, she doesn't know what to do. She starts thinking. Is it fair that she can come back and others can't? Is Revive actually helping people?
From her first death, we also see her experiencing her first love. She has a believable relationship with Matt. Like in any teenage love story, there are a few bumps. But I think that, after so long without friends, she was a bit too trusting. I mean, she gave up her huge secret to her new boyfriend much too easily.
This is a good story that I would recommend to people who want to read contemporary fiction with a bit of a sci-fi twist.