"Gem is a golden retriever puppy who loves to dig. She gets adopted out to a handful of would-be forever families, but no matter how much she wants to please her new people, she can't keep herself from digging up the roses...and the lawn...and the couch cushions...anything that's remotely diggable. Over and over she is returned to the shelter. The folks at the Sterling Center recognize Gem's flaw as an asset. A dog this driven could really shine in...

Ranger, a time-traveling golden retriever with search-and-rescue training, heads to Normandy on the morning of the D-Day invasion where he meets Leo, a Jewish boy who is hiding with a local farmer, and Walt, a young American soldier fighting to free France from the Nazis.

Traveling back in time to a 20th-century expedition to Antarctica, Ranger, the time-traveling golden retriever, befriends a cabin boy working for Captain Robert Falcon Scott and helps them race against rival explorers to reach the South Pole.

The mysterious box that Ranger the golden retriever found in the garden transports him back to first century Rome, where he must rescue Marcus, a young servant boy, and Quintus, a volunteer gladiator, from the brutal world of the Colosseum.

This time the mysterious box that Ranger the Golden retriever found transports him to a Maryland plantation before the Civil War, where he must help a young house slave named Sarah and her younger brother Jesse find their way to the Underground Railroad and North to freedom, before Jesse is sold to a plantation further South.