The Menagerie is what passes for the ruling council of the galaxy, a galaxy known to some as Milky Way. It is made of groups of sentient (and incidentally paranoid) machines that have mostly evolved from biological ancestors and in many cases exterminated them. Two of these hyper-intelligent machines, one of mysterious descent and another evolved from gung-ho giant mantis shrimp-like animals, embark on a dangerous journey of exploration to Andromeda...