The Emperor Of Nihon-Ja: John Flanagan

Book X of Ranger's Apprentice. Horace is missing. Months have passed since he was sent on a military mission to the court of the Emperor of Nihon-Ja but he has failed to return. Evanlyn is worried and she sets out in the company of Will and Alyss to discover what has become of their old friend. It seems that Horace has become embroiled in Nihon-Ja politics. The Senshi sect has rebelled against the rightful Emperor and Horace has stayed to lend support to the deposed ruler. Horace and Will must find men to face the highly trained Senshi warriors as Alyss and Evanlyn must overcome their longstanding rivalry to seek aid from a mysterious group of mountain dwellers. Cover art by Jeremy Reston.