Paladin by Dave Luckett

Scholastic, 2010. ISBN 978 1 862918672.
(Ages Middle school) Recommended. Fantasy. Sam and Finny were at the same school. Sam knows that Finny has dropped out and is aware that she is different, even strange, compared to others at school. But when she is attacked in the park, her attacker is replaced by an old man who tells them both to follow him. Sam finds himself in a different place, a medieval land where time has a different meaning from his own world, and here he is welcomed as a paladin, a good knight with powers that will help those around him. Perplexed, Sam must follow the lead of Finny who he has discovered is a mage with magical powers, and together they are to be trained to rid the world of the dark forces which are threatening to take over. But when Finnny disappears, Sam must act, or the others will keep on believing that she has crossed to the dark side and is now an enemy to be sought out and killed.
A high fantasy adventure story, Sam's quest, to rescue Finny takes him through lands where he is at times treated as a friend sent to help, and other times as an enemy to be fought. The adventures come thick and fast as he must pit not only his wits, but also his strength against an unknown enemy. Several plot twists will retain the heightened interest of the readers, leading to a most satisfying conclusion.
Fran Knight