When Tanner Dog meets the cat next door, they decide to go to explore the park.
Mr. Vlad the cat knows that not all dogs and cats get along, and at first he's careful with his new friend. When Tanner Dog asks Mr. Vlad if he wants to go back to the park, Mr. Vlad says he needs to check his work schedule.
That's when Tanner Dog learns that Mr. Vlad is a professor of knowledge who spends most of his time reading books from the library.
Tanner Dog tells Mr. Vlad that he's a private investigator, and that the two of them should team up to investigate mysteries. "You can do the research from your library books. Then together we can understand things we are curious about!" he says.
Mr. Vlad agrees, and the first mystery they investigate is, "What is a best friend? "
The question leads to a series of adventures that ends with a startling answer that will change their lives forever.
