Richie Millstone, the Firewater Dragon & the Gemstone Cities is the second book in a ten-part series. It takes off where the first left off. Richie and his companions are trapped on a time machine ship lost far from home. They long to get back but are enjoying the adventure. The kids unwittingly get into all kinds of shenanigans as they try to return home. In the first book, they visited Mars of the distant past, one point five billion years, to find a 1930's era civilization with feline ancestry. This book sees them visit even more exotic places while they fight to keep a powerful energy crystal out of the hands of a nefarious dragon. The crystal is rumored to have fallen from outer space and gotten its power by passing through a neutron star. Throughout the adventure, the kids learn about themselves and their future destinies.