Fringe: The Firefly

"The Firefly" is the 10th episode of the third season of the American science fiction drama television series Fringe, and the 53rd episode overall. The episode centers on a chain of events created by Walter crossing over into the parallel universe in 1985 that has had subtle but significant effects in the present. Christopher Lloyd guest-starred as retired rocker Roscoe Joyce. As the first episode in its new Friday time slot, "The Firefly" aired on January 21, 2011 in the United States to 4.88 million viewers, outperforming the previous episode "Marionette" Thursday night viewership by 18%. Time shifted viewership added 42% in its ratings. It received generally positive reviews, with many praising the storyline as "elegant" and "beautiful."