Escape from the Twin Towers (Ranger in Time #11)

Ranger the time-travelling Golden retriever was trained for search-and-rescue and even though he did not pass the tests he has used his training on his many trips to help people caught up in disasters; now he has arrived at the World Trade Center on the morning of September 11, 2001 just as the first plane hits, and he must rescue fifth-graders Risha and Max who are trapped in the wreckage, guide them to safety, and hopefully reunite them with Risha's mother who works on the ninety-first floor.