From Chapter 2

Sigrid and Magnus are bathing in an outdoor natural hot spring with their friends when something extraordinary starts to happen.

The two younger boys started jumping up and down beside Sigrid, splashing hot water into her face.
     ‘Stop it!’ she screamed. ‘What in Thor’s name are you doing? Stop, STOP!’
     For the splashes were becoming more and more violent – even though the boys had stopped jumping up and down. She tried to get up. But the sloshing water kept throwing her off balance.
     Then Asny started to moan: ‘O-oohh. Aaw. I feel all dizzy...’
     Something extraordinary was happening. The hot pool itself seemed to be lurching about, water splashing right over the rim. It was as if a giant was shaking it from side to side.
     ‘This isn’t our fault,’ protested Kari.
     KKKRAGHHAHRRGH! KKKRAGHHAHRRGH!
     His words were drowned by a series of thunderous blasts that came rolling at them from somewhere beyond the far side of the river. The next moment, the sun disappeared. The air grew murky and dim.
     ‘Yuck! What a stink!’ groaned Asny. ‘Now I feel sick too.’
     The bad eggs smell hanging over the pool had grown so strong, it was like sitting in a liquid dung heap. Dry, warm dust coated their lips. They could scarcely breathe.
     ‘Get out the water!’ yelled Ref.
     Frantically, clumsily, coughing and spluttering, they all hauled themselves onto the rocks.
     The quivering ground slowly stilled. They stood up unsteadily.
     ‘Whoo!’ cried Magnus. ‘Look at that!’ He pointed across the wide river valley.
     Pale against the eerie darkness, a gigantic plume of smoke was swelling over the peaks of some distant, snow-capped mountains. 
     The blasts grew even louder. An uneven line of brilliant  yellow  flames  suddenly  burst  into  the   sky, shrouded in red smoke.   
     ‘Freyja’s tears! It’s just like it says in that poem about the gods,’ breathed Sigrid. ‘It must be Ragnarok – the end of the world! Wolves will swallow the sun… The earth will tremble…’
      Magnus began to giggle. ‘Don’t be stupid. This isn’t Ragnarok, you numbskull. It's an erupting volcano!'

From Chapter 15

The two children have received a mysterious warning to ‘Beware the Rings of Doom’.  As their family puzzles over what this might mean, a chieftain visits their house and offers a terrifying explanation.

     A pot of Ma’s best blood sausages was bubbling away over the fire. Sigrid’s mouth watered.
     Chieftain Lygari was in the middle of telling the family all about last year’s meeting of the Great Thing. He was very entertaining, and kept making them exclaim and chuckle over juicy bits of gossip about the other chieftains and their wives. However, every so often he spoke of more serious matters. At this, Magnus nodded earnestly, and once or twice even interrupted to ask some questions.
     ‘Show off!’ Sigrid hissed at him.
     ‘Shut up, you ignoramus!’ Magnus hissed back.
     To their great embarrassment, Chieftain Lygari turned his head in their direction. They both blushed and sat up straight.
     ‘Stop arguing, children,’ said the chieftain. ‘Sigrid, you need to listen very carefully. Your mother has asked my advice about the mysterious silver rings that you inherited.’
     ‘Oh!’ cried Sigrid. ‘Are they…?’
     ‘I’m afraid they may be a dangerous trap,’ said Chieftain Lygari.
     ‘I was right,’ cried Magnus excitedly. ‘He reckons they are the Rings of Doom!  He  thinks  the trap’s been set by that villain Grim Gruesome! You know, the evil child killer – the one that you’re always trying to scare me with…’
     ‘Sigrid!’ said Ma severely. ‘You should be ashamed of yourself. Fancy frightening poor Magnus like that!’
     Chieftain Lygari pinched the face-cloth over his nose and blew on it loudly, staining it with a splodge of wet, yellow snot.
     Under cover of this noise, Sigrid muttered, ‘There you go again, getting me into trouble, you brat.’       
     ‘Are you listening, Sigrid?’ frowned Ma. ‘Grim Gruesome isn’t just a character in a story, you know. He’s a real, live thug! And the chieftain says he’s hiding in Iceland – possibly somewhere nearby!’
     Chieftain Lygari cleared his throat gratingly and went on: ‘Indeed, Sigrid. Grim Gruesome is probably lurking in the mountains across the river.’ His voice was very solemn. ‘I fear that he sent these mysterious rings to mark you both out as his next victims.’
     Sigrid went very pale. ‘Sorry, Ma,’ she said in a small voice. ‘Honestly, I had no idea that Grim Gruesome could really come anywhere near here.’ She bit her lip and shivered. ‘Oh, Chieftain Lygari, sir, please save us from him!’

From Chapter 36

In their quest to save Magnus from the evil Grim Gruesome, Sigrid and her friends find themselves fighting a hopeless battle in a dangerous landscape of boiling mud pools and volcanic steam jets.

Sigrid was literally frozen with terror. She didn’t run down to the Fiery Holes with the other three children. She didn’t even peer over the ridge to watch them. Instead she squatted beside the grazing horses, biting her nails and snivelling.
     ‘Sigrid!’ Asny came racing back. ‘It is Grim Gruesome down there!’ She spat out the news in short, breathless gasps. ‘He’s forcing Magnus into the boiling mud. Elf is all spooked, she’s bucking and rearing…!’ 
     Sigrid groaned.
     ‘Stop blabbering and get up!’ snapped Asny. She slapped Sigrid’s face. ‘You’re the only one who can calm a horse in that state – you’ve got to come!’
     She hauled Sigrid to her feet, pushed her across to Faithful and into the saddle, then steered the horse round  to  the  ridge,  nagging and scolding mercilessly until Sigrid began to ride down the slope.
     At the bottom, Faithful carried Sigrid round a wafting cloud of steam. Then he suddenly stopped and swished his tail – for  Ref and Kari were standing a short way off, white-faced and trembling...and just beyond them was Grim Gruesome!
     The brute seemed to have grown enormous. His cloak billowed monstrously in the wind and he was brandishing two heavily blood-stained swords. Sigrid’s heart turned over. She tugged at the reins – but Grim Gruesome had already seen her.
     ‘Come and share the fun, while I beat up these two maggots, Sigrid,’ he roared. ‘Help me whet my appetite before I cook Magnus and gobble him up – and make your great wish come true!’
     He hurled one of the swords at Ref, lunging at him with the other one. Sigrid screamed. Faithful snorted and galloped on.
     They heard the ominous sound of horse-rattles. Then they passed through more steam and emerged in an area with bubbling mud-pools on every side. And there was Magnus! He was clinging precariously to Elf’s back, shrieking with terror as the white horse sprang around crazily after the great black stallion, Haski.