Holmes and Watson are “partners in crime” but only because they are gay in the Victorian era, which is a crime. That and I guess also because they hit a man with a chair and like trespassing and all that but it’s mostly the gay thing.

You could mute the entire show, replace the dialogue with a generic static noise, and the plot would still clearly be- "Two men communicate solely via desperate, soul-searching eye contact while a crime occasionally happens in the background."