The Caller is the rewarding conclusion to Juliet Marillier's Shadowfell trilogy, in which Neryn and her allies finally confront King Keldec in a battle to reclaim Alban from his despotic rule.

Picking up where Raven Flight left off, Neryn is continuing her quest to complete her training with the Guardians before the planned Midsummer rebellion. As winter approaches Neryn joins the the Guardian of the Air, but the White Lady is fading and when her haven is destroyed, Neryn is forced to move on. Though Neryn still needs to seek the wisdom of the Master of Shadows, time is running out and when she learns of the horrifying new threat to the rebellion, Neryn has no choice but to enter Keldec's court.

One of the strengths of this series has been Marillier's characterisation of the principles, Neryn and Flint and their struggle to reconcile their own conscience and behaviour with their need to serve the greater good. Never is the conflict more clear than when Neryn is forced to witness the King and Queen's cruelty in Keldec's stronghold, and remain silent. Despite the personal cost, Neryn has be hold strong, trust in herself and her allies, in order to defeat the King and his dark forces.

Flint is near his breaking point in The Caller, struggling with the deeds he has had to commit as an Enforcer in order to provide the rebellion with what they need. Marillier explores his conflict with authenticity and compassion.

Though there is never any doubt that Neryn and her allies will prevail, the final confrontation is as stirring as to be expected with impassioned speeches by Flint, Tali and Neryn, and a violent conflict that leaves several of the characters the reader has come to know and love dead on the battlefield. It is a rousing finale.

Overall, the Shadowfell Trilogy is an enjoyable young adult series and The Caller provides a fine conclusion to Juliet Marillier's tale of fantasy and adventure.