The Black Lotus by Kieran Fanning is the first book in the Samurai Wars series. It is a fantastic combination of explosive ninja action and time travel with a big flavour of Japanese culture. It's very humorous and will rock the 9+ age group.
If this story sounds up your street, then at the bottom of the post you can read an exclusive chapter. Hopefully, this should whet your appetite until you get to the bookshop to purchase a copy. It is out now in paperback for £6.99 by Chicken House.
Ghost, Cormac and Kate are not like other kids. Ghost can turn invisible, Cormac can run up walls and Kate can talk to animals - all abilities which make them perfect recruits for the Black Lotus, a training school for ninjas. But when the Moon Sword - a source of unimaginable power - is stolen by samurai, the three are forced to put their new skills to the test in sixteenth-century Japan.