In the sixth novel of this innovative series, the Time Soldiers can finally choose where—and when—they want to travel. When they journey to the city of Edo in ancient Japan and encounter an elderly Samurai warrior who has one regret, they help him change the past, and in doing so discover another piece of the mystery of the time portal and the green stones scattered throughout time. This remarkable series couples classic photography and bold images with an engaging story that encourages young readers to become lifelong learners and comes with a full-color teacher's guide.