"The Great Mouse Detective" with an alternative detective story

You are a mouse detective who lives on Baker Street, and for several years now you have been trying to catch the evil villain, your worst enemy and Napoleon of crime - Ratigan! You were even able to mess some of his plans, but that was never enough to truly win over him. Who knows what this evil mind is plotting now and whether you can stop him this time...

What a miracle that Dr. Dawson decides to move in with you on this rainy day, based on your advertisement, where you mentioned that you want to live with someone to share the rent...

(Note: This is a very big project, and it has some flaws. If you will find something weird, don't afraid to share it in the comments.)

(Proxies recommended)