Artemis Fowl and the Time Paradox by Eoin Colfer

Book six in the Artemis Fowl series.

Artemis's mother is dying. When Artemis tries to use the last of his stolen magic to heal her, he only manages to make her condition worse. After summoning Holly to help, he discovers that his mother has a magical disease called spelltropy. The only known cure comes from the extinct African lemur. Artemis caused the death of the last one while trying to fund an expedition to save his father.

Artemis guilts Holly into traveling back in time with him to undo the damage and save that last lemur. They race against time (literally) to save the lemur before it is too late.

But even with the help of the demon warlock, No. 1, events might get too twisted to ever untangle. Not only does an old enemy reappear, but Artemis must also face a 10-year-old Artemis, who is ruthless enough to sabotage the entire mission.

I was disappointed that Artemis's love interest from the previous book never showed up. I also wanted to know more about the demons. Mulch Diggums is my favorite character and did not have as much fun as in previous books. While the book kept me entertained, the story became difficult to follow as it kept twisting in on itself. That pesky time paradox...