Heretic follows on from Vagabond and Harlequin. It’s taken me 9 years to completely forget what happens in the book. I first read it while on holiday in 2012 and gave it five out of five, and expressed a hope to read books one and two (little did I know there was a fourth instalment published 9 years after this one in the form of 1356 ). Heretic was a good read, perhaps because most of it is totally made up and not tied to actual historical events, apart from the plague. Note there are major spoilers below.

Heretic begins in 1347 in the early stages of the Hundred Years War with a battle outside the walls of Calais which leads to a truce with the French. Most of Cornwell’s books open in a similar fashion to whet the readers’ appetite for mayhem. Our hero the English archer Thomas of Hookton, in the service of the Earl of Northampton, is ordered to continue his search for the Holy Grail and as a side quest to confront his cousin Guy Vexille who is also intent on finding this most esteemed of relics.

Thomas takes a small band of men at arms and archers into Gascony to break the truce and take control of the fictional bastide Castillon d’Arbizon. Among his band of merry men are the outlawed French knight Sir Guillaume and the ransomed Scot Robbie. They are soon joined by another principle character, and perhaps the heretic of the tile – although Thomas and Guy Vexille could also be considered heretics – the predictably beautiful Genevieve who Thomas rescues from being burnt at the stake as a witch by the inhabitants of Castillon d’Arbizon.

Thomas predictably falls for Genevieve, but so too does Robbie and this drives a wedge between them with Robbie’s jealousy fuelling his desire to condemn her to a fiery end and turning some of Thomas’s god-fearing men against him. Thomas goes to the valley of Astarac where he thinks the grail might be hidden in the church of his ancestors. Here he runs into the hot-headed son of the local Count of the fictional town of Berat with the rather effeminate name of Joscelyn, a bunch of lepers, some monks, a wily priest and last but not least Guy Vexille whose travel companion is in the pay of an ambitious bishop who wants to become pope and has spent a lot of money making a fake Grail.

There’s twists and turns aplenty with the plot seeing Robbie and Thomas’s friendship totally broken and Thomas excommunicated from the church and on the run in the woodlands of Gascony with Genevieve. The whereabouts of the true Grail is still a mystery, although Thomas does come into possession of an empty box which he suspects held the Grail when it was hidden under the church at Astarac.

The story reaches a very satisfactory conclusion back at the besieged Castillon d’Arbizon. The remains of Thomas’s faithful team of archers are holding the inner castle of the town with Sir Guillaume against the combined forces of Joscelyn, now Count of Berat after bumping off his sick father, with Robbie now in his service, and Guy Vexille’s and his men at arms. Thomas breaks through the blockade with Genevieve and a ragtag band of roaming bandits. He joins the defenders and helps to overcome the first wave of attack. However things are not looking good as they face overwhelming odds and so he displays the fake Grail he found among the possessions of one of the soldiers he killed to get to the castle.

Seeing the ‘Grail’ gives the attackers pause and so too does the sickness which is spreading rapidly among their men. Thomas knows the thing is a fake because it doesn’t fit the box they found earlier, but he pretends it is the real deal in the hope of stopping the attack. However, this doesn’t transpire and so with more and more people falling in, Vexille, fuelled by his desire to own the Grail and see in a new period of a true Church, foolheartedly decides to mount a last-ditch attack despite the dominance of the few English archers left alive.

In a thrilling climax inside the castle courtyard Thomas finally kills his nemesis despite his thick armour – Thomas’s bodkin arrows and strong bow arm are just too much for his adversary. Robbie manages to survive the plague and makes his peace with Thomas. Thomas travels back to England, to Hookton, with Genevieve, and finds the actual real Grail – a lowly object quite clearly flagged as a potential candidate for the relic if you’ve seen Indiana Jones and the Last Crusade. However, given all the trouble it has caused Thomas decides to make sure no-one will ever find it again.