Abacus is an adventure story in which 12-year-old AP, who's into science, travels through time with Kate, his 15-year-old sister. Kate thinks her geeky brother is a waste of space, but when he uses science to get them out of trouble, she starts changing her mind. Their journeys take them to medieval England, the Wild West, and to ancient Egypt, where AP's science is seen as magic. And stalking them on every trip is a hooded stranger whose attacks show he'll do anything to stop them.
Unlike the spells woven by that very famous boy wizard, AP's 'magic' is real and readers will be able to repeat the hands-on experiments themselves, using instructions at the end of the book. "I thought the science experiments that AP performed were ingenious," wrote 13-year old Justine, one of the early readers of Abacus.