Run (Fearless, Book 3), by Francine Pascal
While Sam was chasing Gaia in "Sam," someone working for Loki (that's what the "L" stands for) caught him. As "Run" opens, it is Monday morning, and Gaia gets an email telling her that she has only until 10:00 that night to save Sam. You see, Sam is diabetic and he hasn't had his insulin since Saturday. As a result, he won't last much beyond 10:00.
Loki sets Gaia a series of tests, many of which seem to make no sense, that she has to pass before she can get Sam back. We see through this just how far she will go, and possibly more importantly, how far she won't.
Where "Sam" was light on plot, "Run" is heavy on it. However, similar to "Sam", most of the plot is action. This volume pretty much sticks to Gaia's neck of the proverbial woods -- from the brownstone to school, then to the park, then back to school, and so on. And everywhere she stops, she either gets some form of communication from Loki or has a test to pass. Sometimes she gets both communication and a test.
Throughout the day, we also see evidence that Gaia is under close surveillance. Someone is filming her, but who is it, and how can someone get so close to her with a camera without her noticing? Hopefully this will not remain an unanswered question for too many books. I'm pretty sure it is not Ella, since Gaia should definitely be good enough to notice someone she knows following her around like that.
Ed is shaping up to be a pretty good sidekick and an excellent friend. He follows Gaia through a lot of this very difficult day (though he does have to go back to school for a chemistry test, which he thinks he probably got a C on).
We also find out that Sam has some kind of depersonalization issue going on. Depersonalization is the feeling that you are not connected to your body. Fleeting periods of depersonalization are normally the result of things like anxiety, stress, or migraine. However, Sam has something more than that here. He almost never feels connected to his body. This level of depersonalization is usually considered to be a form of dissociative disorder and results from some kind of trauma. We do know that Sam was a geek until he reached middle school, at which point his parents took him out and got him braces and a new wardrobe.That certainly doesn't seem to be the kind of trauma that results in chronic depersonalization, though. It should be interesting, if a bit harrowing, to find out what was.
We see more of Tom and his concerns about Gaia. Since she thought that Loki was Tom the first time she ran into him in "Sam," Gaia has decided that Tom was a sociopath. I do wonder what the ultimate fallout of that decision will be, but we don't find out here.
And now I get to haunt used bookstores searching for the rest of this series.