After the first three Not Quite Human books involved petty crimes being committed by teeangers, and Chip the android helping to solve them, the fourth one goes in a different direction and instead deals with Chip being taken over by a hacker. Now Chip isn't the one solving the mystery, Becky and Dr. Carson are.
The blend of sci-fi, comedy, and mystery solving established in the previous books continues with a greater emphasis on mystery and suspense, as Chip's odd, seemingly random behaviors given him by the hacker attract a lot of attention and put people in danger. It's a faster moving plot than the previous books, not that the other two were slouches by any means.
The story is still as implausible as before. Even moreso, in fact, with Chip's odd behaviors being explained away as him having a powerful fever. So, kids somehow believe that a high fever can make someone go nuts in a movie theater, pretend the movie is real, then run outside and climb a tree? Or a fever can make someone take all the plates in the lunchroom and stack them on top of each other?
The kids have shown an unusually high tolerance for Chip's mannerisms and speech patterns, all the result of him being an android. This is understandably necessary to keep the story going, because if the kids all bullied Chip, it wouldn't be a very fun story. But to have them willing to tolerate him acting crazy and excuse it as a "fever" is asking a bit much.
But when you're working with a story about a robot disguised as a kid going to middle school, you're already asking the reader to suspend disbelief. And frankly, if you're willing to suspend it a little bit further, this is a pretty fun story.