This series is amazingly bizarre, Amazingly Funny and leaves you guessing where the story is going often leading you down a rabbit hole that only concludes when you've looked at the most improbable solution to the problem possible. Dirk Gently is a detective who solves cases Holistically believing every thing is interconnected in the universe and that by pursuing every solution for one case he will often solve other cases, while this often appears to his partner McDuff like he is doing nothing on one he has a way of one thing from one case coming back and helping him work the other cases. His cases aren't always simple cases with obvious clues though as they often result in super science and solutions that push improbability to the limits.
The two lead characters personalities play off each other well and the actors do a good job establishing these traits.