I have written a new middle-grade sci-fi/fantasy called Earthscape. It is planned as the first in a series called The Timeline Chronicles.
It is aimed at 8-12-year-olds

13-year-old Morgan Lane, a catcher of lost memories, is on a quest to rescue Princess Leila, imprisoned in Doomguard on a parallel Earth, who has forgotten the spell that will save her life; all before the timeline closes and traps him there forever.

Gifted with a superhuman memory, Morgan inherits a mystical chronometer that is also a time machine. Together with Lin Rainbow, his sassy adopted sister from Trinidad, who possesses an enchanted amulet, Morgan finds himself on Leila’s version of Earth which has two moons and where dinosaurs evolved into intelligent saurians, and apes into furry sapiens - with not a Homo sapiens in sight.

To save Leila from her fate, Morgan and Lin must cross the deadly Fleshwarp swamp, battle their way through the nightmarish tunnels of Droth and cross the Soundless Plain to the Forest of Gloom. They face dangers from renegade creatures, mechanical animoids, flying avids and deadly sand eels before reaching the fortress of Doomguard, rescuing Leila and returning her spell. 

.