“Mirror, Mirror” is episode eleven of season five of Eureka.
In the previous episode, “The Honeymooners”, Grace was revealed to have been the spy at Global Dynamics. She was also protecting someone else – when Henry quizzed her about who it was, she said that it was him. Of course, it wasn’t exactly him, it was the Henry that existed before this Henry and the others went to the past in “Founder’s Day”. So Henry is technically guilty of something he didn’t do.
Holly now has her new body, and is deciding what to do. Before she decides she gets a message, reminiscent of something seen in “Ex Machina”, which results in her acting oddly.
Meanwhile, a cloud of smart dust intended to stop climate change is misbehaving, and will eventually start interfering with brain functions.
The story doesn’t conclude in this episode, but continues in “Double-Take”.