Over Here Astrid gets an unexpected visit from her Alternate, while Peter and Olivia track a killer using a toxin that has yet to be invented. Both universes collide in a case that pushes the boundaries of what is possible.
Great episode. I always wondered how agent Astrid Farnsworth from the other universe was able to do so many calculations during the other episodes, but this episode made that clear. She is an autistic savant with amazing mathematical calculating abilities.