Ep 18. The Consultant

In Fringe season 4 episode 18, titled "The Consultant", the Fringe team investigates a case involving a man who seems to have the ability to turn invisible. As they delve deeper into the mystery, they discover that the man is actually part of a group of genetically enhanced beings called "Observers".

Meanwhile, a consultant named David Robert Jones (played by Jared Harris) begins making contact with Olivia and offering to help her uncover the truth about the Observers. However, it soon becomes clear that Jones has his own agenda and is working with the Observers to bring about a major event that could have catastrophic consequences.

As the Fringe team races to stop Jones and the Observers, Olivia must decide whether or not to trust the enigmatic consultant and if his information may be the key to saving the world. The episode is full of suspenseful twists and turns that keep viewers on the edge of their seats until the very end.