During one of her parents' digs in the Valley of the Kings, Theo and brother Henry stumble on the sarcophagus of Amenemhab, great general of pharaoh Thutmose III. When Theo touches Amenemhab's Eye of Horus amulet, she has a fleeting vision of a woman in the desert.
Certain that Alistair has been cursed, Theo is desperate to find a cure. But no-one will believe magical curses are real. Besides, Alistair and Henrietta have more important things to worry about - the arrival of Safiya, an Egyptian princess, and her influential uncle.
Trapped in Vincent's secret basement by the transformed Vincent/snake, Theo and company manage to flee by crawling up the coal chute. Theo nabs Vincent's magic book on the way out, hoping to use it to find a cure for her father's curse.
Theo makes a plan to put the museum's magic safe into effect. Unfortunately, Clive wheels in an enormous Ancient Egyptian false door, covered in powerful magic. Matters go from bad to worse when Will and Henry accidentally open a portal and are swept away.
Theo has a vision of the Penny Arcade surrounded by flames and filled with chaos. She sees a man in a mask, looking straight at her, asking who she is. Determined to find out what's going on, Theo heads off to the arcade with Henry.
Theo is checking all is safe on the Egyptian Floor one night when she discovers that the Eye of Horus's magic seems to be changing. Next day, Henry tries to persuade Alistair to use his latest invention. Unfortunately, the machine has more than a few teething problems.
Theo, Safiya and Henry are studying art at the museum when Theo has a vision of Queen Hatshepsut, warning her that the Serpents of Chaos want to use the Eye of Horus to guide them to the Staff of Osiris. She hurries off to magically protect the museum, helped by Henry.
The Chief Serpent's plans are advancing - in three days' time there will be a total solar eclipse. When it happens, the Eye will show the way to the enormously-powerful Staff of Osiris, which will give the Chief Serpent the power to unleash chaos.
The gang are gathered at the museum. It's time to get the Eye back out of the Serpents' grasp and Theo has a plan. Armed with plans of the Serpents' subterranean lair, plus Will's magician's way with distraction, they'll sneak into the Serpents' base and grab the Eye.
Will and Safiya are at the Arcade, where Will has hidden the Eye. Meanwhile, the museum is under observation by a burly Serpent. Theo and Henry plan to sneak out to join the others, but are stopped by Henrietta. At the Arcade, the Zoltar fortune teller starts acting up.
Moments after Theo and Safiya's disappearance, Henry covers for them, while Will picks up the invisibility rope Theo dropped. Meanwhile, Theo and Safiya find themselves in the desert, with no way back home. Their only choice is to follow the glow of the Eye.
Theo uses her magic to try to cure Will's invisibility, but nothing seems to work. With no alternative, she risks using the Staff of Osiris to augment her magic. She succeeds in restoring Will but the surge of magic from the Staff is strong enough to alert the Serpents.
The Staff has unleashed chaos across the globe. Theo is determined to go to Cleopatra's Needle, to stop the chaos magic and save her brother. Theo tells Will and Safiya they need to collect magic items from within the museum to battle the Serpents with.
The Serpents of Chaos are defeated and all seems well, until a statue with a will of its own leads Theo and her friends to a brand-new mystery.
Will and Safiya are trapped inside the secret room, the walls are closing in and Theo will need all her magical power to save them!
Determined to unlock the secrets of the hidden room beneath the museum, Theo casts a spell to help decipher the secrets of her grandfather's journal with disastrous results.
When Will, Safiya and Henry are swept into dangerous dreamworlds by the pyramidion's power, Theo must race to save them before it's too late.
Will is intent on impressing with his new magic show but will the pyramidion's power turn his dreams of fame into a magical nightmare?
When powerful magic is unleashed at Theo's fifteenth birthday party, it looks like someone is after the pyramidion's world-threatening secret.
Theo must race against time to save her parents from a deadly trap beneath the Sphinx and stop the giant chaos-snake Aapep escaping his prison beneath the Great Pyramid of Khufu.
While Theo and Will try to discover what the Serpents of Chaos are planning, back at the museum Safiya, Henry and Lady Throckmorton find themselves facing a strangely familiar monster.
Theo faces danger close to home when she discovers someone or something has been stealing magical power from the museum.
Aapep is loose in London, on the hunt for Heminu's flail and the museum's mummies have developed a mind of their own!
An accidental body-swap forces Theo and Safiya to pretend to be each other for a day, just as Safiya's parents arrive for a long-awaited visit.
Will risks a return to Aapep's lair, while Aapep himself forces Nigella to seek out and destroy Theo forever. In the meantime, Lady T follows clues for answers in Paris.
Time is running out and Theo and her friends must face the snake of chaos Aapep himself if they're to save the world from destruction and stop him swallowing the sun.