It’s not easy being a teenager, and it’s no different for Rahim, who is trying to balance everything in his busy Philly life: school, parents, bullies, his secret hopes of becoming a hip-hop star, and the constant schemes of his brilliant best friend, Kasia. When Kasia invents a new kind of cell phone that is also a time machine, it sends Rahim into the past, where he must outmaneuver a secretive government agency without altering history's delicate balance. This electrifying book puts Rahim and Kasia at the center of an ever-widening mystery that will illuminate their own pasts (and futures) and test their friendship. Dynamic and richly written, with crisp commercial prose and charming interior illustrations, The Rhythm of Time is an infinitely readable sci-fi adventure that is sure to delight younger readers.