One of your friends is about to do something extremely dumb.

She never was one to make good decisions, but this time she’s made an awful one. It involves boys and sneaking out, a party somewhere out of town, a good chance for big trouble, and, well, you’re no snitch but somebody oughta know. This could turn out very, very badly.

So what do you do when a friend is in a potential mess? For Chanti Evans, the answer is clear: detective work will keep her friend safe. In the new book, “Creeping with the Enemy” by Kimberly Reid (c.2012, Dafina Teen, $9.95 / $10.95 Canada, 256 pages), the challenge is to weed through the lies.

The robbery at the tamale place made no sense.

It was Freebie Friday and their buy-one-get-one offer usually meant a line out the door. But almost nobody was there, and 15-year-old Chanti Evans noticed. She also noticed the guy who was flirting with her friend, Bethanie. There was something really wrong about him.

First of all, he acted weird when the gunman entered the restaurant, like Creep-O was some kind of hero. But he almost got everybody killed. Having fled the scene herself, Chanti checked around the avenue for the 4-1-1 and got nothing. Her mother, Lana the cop, had forbidden Chanti to visit the bodega’s dangerous neighborhood, so she couldn’t exactly ask Lana.

Truth? Chanti would probably never know what really happened.

Thing is, she hated lies, but it seemed like her whole life was based on them. She lied to her school’s headmistress about Marco Ruiz, whose parents forbid him to see Chanti, even though Marco was actually Chanti’s sort-of boyfriend, which was scary because she’d never had a boyfriend before.

Then there was the lie of not going to the tamale place, but it was more of an omission. It was hard to fool Lana; she was always on alert. And besides, though Chanti and Lana were tight, Lana kept her own secrets, too.

And then there was Bethanie. She was actually dating the creep from the bodega and things didn’t add up, especially the lies Bethanie told about herself. Bethanie’s whole life seemed to be one gigantic lie.

Everybody hated Chanti’s snooping. But what else could she do?

So you love mysteries, but the books your mom read back in the day are too old-school for you? Then try “Creeping with the Enemy,” set in a new kind of school with a street-smart sleuth.

And that sleuth–she’s the best part of this book. Author Kimberly Reid gives Chanti brains, maturity, and a sense of humor without making her too much of a good-girl type. That, and the unstilted, real-life conversational dialogue both lend authenticity and will keep savvy 12-to-17-year-old detectives from tossing this book aside.

This teen novel is the third in a series and while it could be read first, I think you’ll like it better if you’ve read at least the first installment. Start there, and “Creeping with the Enemy” is a book you have no trouble enjoying.