Probably courage and problem - solving. The mouse detective must be brave to face the challenges and mysteries in the story. And he has to use his intelligence to solve the problems he encounters. Also, there could be a theme of community, where different mouse characters work together towards a common goal.
Well, it has the potential to be. The concept of a mouse detective is unique and interesting. In children's literature, having an animal as the main character is quite common, and if this novel has a well - crafted plot, memorable characters, and positive themes, then it can definitely be a classic.
One way is to give the human a unique backstory. For example, if it's a detective in the Great Mouse Detective world, he could have a past that led him to be interested in solving cases in both the human and mouse worlds. Maybe he grew up near a place where the mice and humans interacted a lot, so he has a natural curiosity.
A human can be a helper. They could assist the mouse detectives by providing resources that are difficult for mice to obtain, such as certain tools or information from the human world.
One interesting story could be about the great mouse detective solving a mystery in an old, abandoned cheese factory. The clues are hidden among the cheese wheels and old machinery.
Definitely Sherlock Holmes. Since The Great Mouse Detective is inspired by Sherlock Holmes, a crossover with the original Holmes would be very interesting. They could compare and contrast their detective methods.
One idea could be a crossover with Sherlock Holmes in the human world. The great mouse detective could team up with Holmes to solve a mystery that spans both the mouse and human realms. Maybe there's a villain causing chaos in both worlds and their combined skills are needed.
One idea could be Basil solving a mystery in a new, strange part of the mouse city, like an abandoned underground area filled with old secrets. Another could be Basil teaming up with a new, young mouse detective in training to solve a case that's baffling the entire mouse detective community. Or perhaps a story where Basil has to solve a mystery on a ship sailing to a far - off mouse - inhabited island.
You could introduce a brilliant mouse scientist who has created some newfangled gadget that could help Basil in his detective work. Another good character could be a mysterious mouse from a far - off land who has some valuable information about the case but is very secretive. And a street - wise mouse informant who knows all the gossip and rumors in the city would also be great.