Wednesday Weeks just wants to finish Year Six without any more magical mishaps. But Gorgomoth the Unclean has other plans. The tyrannical goblin king is back, and he's hot on the trail of the long-lost Stone of Power. If he finds it, it'll be goodbye school holidays and hello Third Age of Never-Ending Darkness. To beat Gorgomoth to the stone, Wednesday and her friends must prove themselves worthy by passing three deadly trials. And so the race is on. But unfriendly cats, tomato sauce geysers and a pizza-train rollercoaster ride through a live volcano won't make their mission any easier. Will their magic and science be enough to stop Gorgomoth from taking over the universe?

Just when it seems like Wednesday and Alfie might finally be free to get on with their lives without Gorgomoth ruining everything, the Unclean one rears his ugly head again. This time Gorgomoth is on the trail of the long-lost Stone of Power, which he will be able to use to rule the nine realms and bring about the Third Age of Never-Ending Darkness. Now Wednesday and the gang must beat Gorgomoth to the stone and pass three trials to see who is worthy of its ancient power. If they don't win, it might just be the end of the world. The final instalment in the mind-bogglingly fun series that asks the question: in a world of magic, can science save the day?