Halt and Will may have managed to off a couple of Kalkara, but the battle is far from over. "The Burning Bridge (The Ranger's Apprentice, Book 2)" picks up where John Flanagan's first fantasy-adventure novel left off, and it has all that book's strengths with none of the weaknesses -- nimble pacing, vivid writing and a suitably monstrous villain, although the ending is a bit abrupt. 
 King Duncan is preparing for a forthcoming war with Morgarath's forces, and pulls his own armies back to a defensive position. At the same time, Gilan is sent on a diplomatic mission to Celtica, and since the Celts insist on having three people, Will and Horace are sent at the same time. But when they arrive, they find that the Wargals are swarming all over the place, and the native Celts are all missing. The only one left is Evanlyn, the former maid of King Duncan's daughter. 
 While Halt deals with the piggish Sir Montague, the boys stumble across a tunnel and bridge meant to allow Morgarath's army out into the open without the hindrance of steep cliffs -- and a vast collection of mercenary Skandians (Vikings by any other name) who have been hired to help crush the king's army. And to stop them,. Will may end up in the hands of his worst enemies. 
 The world John Flanagan conjures up here is pretty recognizably a medieval England-that-never-was, with hints of similarly semi-familiar lands to explore (Celtica, Hibernia, Scotta, Skandia) and vaguely Tolkienian monsters working for the bad guy. And in "The Burning Bridge" the storyline becomes much darker and more intense, as the action expands from Halt and Will to encompass whole armies and countries. In short, it turns from a potential epic to a full-blown epic. 
 And Flanagan has a knack for fast-moving, detailed prose and lots of suspenseful moments (especially when Horace and Will have infiltrated Morgarath's fortress, full of Celt slaves and Skandian warriors). Flanagan does include some fun comic relief (such as Halt's unique way of dealing with Sir Montague), but the plot overall becomes extremely dark and intense -- lots of skulking, being taken captive by Skandians, and sword-fights with the deadly Morgarath. 
 The only problem? Well, the whole Morgarath subplot is handled nicely, but frankly I wasn't expecting it to dealt with so quickly. Not bad, just unexpected. And the book leaves us on a cliffhanger that presumably is fixed in the next book. 
 Will is also an excellent hero in the Lloyd Alexander mold, and while he still has his immature moments he's clearly matured a great deal -- he's more self-sacrificial, stronger, and able to make decisions under pressure. Halt's bond with his new apprentice has become more evident in their time apart, the quirky Galian serves as a good "big brother" figure, and Horace gets to shine with the most important single combat of his life. And the mysterious Evanlyn adds a strong feminine presence to the plot. 
 "The Burning Bridge" is a great second installment in John Flanagan's solid fantasy series, and it promises to blossom further as the series goes on. Just have the third book on hand.