Quick recap
Artemis's mother falls ill with Spelltropy, a fairy disease whose cure comes from a lemur that 10-year-old Artemis helped drive extinct. With No. 1's help, he and Holly travel eight years back in time to save the animal. In the past, they face young Artemis himself, every bit as sharp, and a Butler who doesn't know them. Along the way they find Opal Koboi behind the Extinctionists, and she follows them to the future. There she reveals she caused the mother's illness herself by possessing her. Artemis tricks her with a toy in place of the lemur and buries her in an explosion. His mother recovers and remembers everything, and Artemis finally tells her the truth.
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