Journey through Ash and Smoke (Ranger in Time Book 5)

Ranger is a time-traveling golden retriever with search-and-rescue training. In this adventure, he goes to Viking age Iceland, which proves to be tough terrain for Ranger to navigate. Usually it's Ranger's job to save the day before he can return to his family, but he meets a girl named Helga who rescues him more than once. And when a nearby volcano threatens to erupt and Helga's new baby brother or sister starts to come early, they must journey through ash and smoke to find Helga's father. But if Helga doesn't need Ranger's help, how will he ever get home?