Desperate, she had no choice but to return to the others. However, her unreliable actions had convinced Veitch that she had something to do with Ruth's disappearance.
With the strain telling, they made plans to investigate the Well of Fire beneath Arthur's Seat, an extinct volcano overlooking the city. Tom told them it was once a tremendous source of the Blue Fire but over the years had grown dormant. Somehow they had to find a way to reignite the Well so the spiritual energy would spread out across that part of the land, weakening the grip of the Fomorii.
Once again they decided to consult the spirits. Shavi visited one of Edinburgh's most haunted locations, where the dead revealed Ruth was still alive, imprisoned beneath the castle where the Fomorii had made their den. Other answers were typically cryptic: the Well of Fire would not be enough to help them defeat the Fomorii. To halt the Cailleach Bheur they would need an extra power, something called the Good Son. There was also a price to pay for the answer-the dead sent the spirit of Shavi's murdered boyfriend, Lee, to haunt him.
Tom knew exactly who the mysterious Good Son was-the Tuatha De Danann god Maponus, missing for millennia. Tremendously powerful, he was the son of Dagda, the Allfather, yet the Golden Ones always refused to speak of what had happened to him. Tom, however, knew Maponus had been imprisoned at nearby Rosslyn Chapel, a mediaeval sacred site renowned for its Celtic and Masonic iconography.
Researching this new information at the Central Library, Church and Laura were attacked by whatever had been stalking them since Loch Maree. After a failed attempt to sever Church's finger, it fled before they had a chance to get sight of whatever it was.
During all this, Ruth was undergoing terrible torture in the secret Fomorii burrow beneath Edinburgh Castle, but while trapped in her cell, a strange thing was happening: her familiar manifested as a voice in her head, teaching her the great secret knowledge that was her heritage. Eventually, Calatin made her suffer the worst torture of all, forcing a large black pearl down her throat.
Finally it was time for the companions to go their separate ways: Church and Tom to find the Well of Fire, Laura and Shavi to seek out Maponus, and Veitch to launch a desperate attempt to rescue Ruth.
At Rosslyn Chapel, Shavi and Laura encountered another Watchman. The chapel's carvings pointed to something terrible hidden there, but although Laura was open to the warnings, Shavi appeared under the control of some spell, driving him onwards. The Bone Inspector was also drawn there by what they were attempting. He tried to prevent them, but they locked him outside the chapel so they could continue. While Shavi and the Watchmen dug into a secret chamber beneath the chapel, Laura listened to the Bone Inspector's warning.
He told her Maponus was struck down by the Fomorii as he attempted to cross over to our world from T'ir n'a n'Og. Whatever the Fomorii did to him drove him mad, so that when he arrived in our world he was an uncontrollable force, slaughtering hundreds and laying waste to many villages. Only a ritual enacted by the Culture, the Bone Inspector's people, could stop him, and then he was not destroyed, only bound in the sacred spot beneath the chapel that was raised up as both a marker and a warning. If he was freed, the Bone Inspector warned, devastation would be laid on the land once more.
Before Laura could act, Maponus was freed, slaying the Watchman on the spot. Laura and Shavi escaped as the mad god stalked out across the countryside. It appeared to be yet another of their great failures.
Back at Arthur's Seat, Tom helped Church through his first steps in learning how to perceive the Blue Fire in everything. The energy guided them through a magical doorway into Otherwordly tunnels beneath the volcano where the two were separated. In a massive cavern where time and space had no meaning, Church experienced visions of the past, present, and future. Reuniting with Tom, they came across an enormous hole plunging down into the bowels of the earth-the Well of Fire-ready to be reignited by what Tom called a leap of faith. Church decided to use the locket given to him by the young Marianne; he had always believed it was a powerful symbol.
Before he could act, Church glimpsed a giant wolf, the same Laura witnessed before Ruth was taken, the thing that had attacked him in the library. Tom told him it wasn't really a wolf, once the old gods had tampered with someone, the results confused the mind's perceptions; the real person lay somewhere behind the perceived image.
The two of them edged out around the abyss to hide, but their pursuer followed them. Church slipped into the well, dropping the locket into the depths. Somehow this created a tear in the fabric of reality. Blue fire licked out, the energy carrying Church, along with Tom, out to the foot of Arthur's Seat, where they could see Fabulous Beasts moving towards the Old Town.
Veitch, meanwhile, had entered the Old Town, where Maponus was already in conflict with the Cailleach Bheur. Making his way past the Fomorii defences into the burrows beneath the castle, he stumbled across a strange ritual where the Fomorii gathered before Calatin and a warrior, bigger and more frightening than all the others.
After rescuing Ruth, the two of them escaped the tunnels to discover the Fabulous Beasts destroying everything corrupted by the Fomorii evil, while the Blue Fire ran out from Arthur's Seat in a lattice of reinvigorating energy; the land was beginning to come alive. Maponus and the Cailleach Bheur were both forced to flee in the face of the Fabulous Beasts. And then, finally, the castle and the burrows beneath were destroyed in the conflagration.
The companions were finally reunited in Greyfriars Kirkyard, but their joy was short lived. The spirits of the dead rose to drive them out, saying they were "unclean." Weary but elated, they fled the city: not only had they rescued Ruth, they had also stopped the plan to bring back Balor.
That night, while they rested by the campfire, they met two minor members of the Tuatha De Danann pantheon who were wandering the land in search of experience. Cormorel and Baccharus told Church if he wished to remove the Fomorii corruption within him he should visit something called the Pool of Wishes in the Western Isles, a fabulous place in T'r n'a n'Og where the home of the Gods lay.
Heading south they came to a strangely quiet village-my village-where people refused to answer their doors after sunset. A few of us were gathered in the local pub and I remember how I felt the moment they wandered through the door. I was a rough and ready journalist. I'd met people from all walks of life, but I'd never met anyone like them before. They were apart from everyone else, as if they'd witnessed things none of us could ever dream of; which, of course, they had.
We rarely saw strange faces in that haunted place so I went over to introduce myself, and to tell them what kind of hell they'd wandered into. For weeks we'd been the prey of strange creatures we couldn't identify. They roamed the lonely fields during the day, but under cover of darkness they came into the village, looking like nothing more than sheets flapping in the wind-but one of our local farmers had seen them reduce a sheep to bloody chunks in seconds. Some people died before we learned they couldn't get into houses past locked doors. But even though we'd warned everyone to lock their doors at sunset, people were still getting killed in their homes. It was a mystery we couldn't understand. Naturally, those six brave people agreed to help us solve our problem.
After Shavi expressed his guilt at freeing Maponus, Church summoned Niamh, who agreed to marshall the Tuatha De Danann to bring back their errant god on one condition: that Church broke off his relationship with Laura so that he could learn to love her. Although it confirmed what Church had suspected about Niamh's feelings, it was still a shock. His relationship with Laura was in a state of flux, and he had no idea how he really felt about her, but to put her on one side seemed so callous. Yet the burden of responsibility proved too great. How could he set their petty emotions above the chance to prevent Maponus murdering more people? He agreed, reluctantly, and though he didn't recognise it at the time, his decision was swayed by that strange emotional power the Tuatha De Danann held over mortals.