Timecrack by William Long

An exciting sci-fi/fantasy adventure about two young brothers who are swept into a timecrack, a portal that takes them through time and space into a parallel universe. There the teenagers search for their missing parents, who were also taken by a timecrack from the archaeological dig deep in the Yucatan jungle of Mexico. The young brothers encounter Anton and his brother, escapee from Mars, who want to kill them. They find friends, including the Lancers in their flying machines, and the Androts, human-robots, who are the protectors of the Amasian cities on New Earth. This is a gripping adventure from page one to the very end of Timecrack.