Fringe’s plot has been well planned since the start. Says one of the producers:
[...] we’ve been setting up season four in brushstrokes very early on in season two, [...] we’ve been sort of setting up season five since season one.I love it when shows do that. “Lost” was also great when it came to long-term plotting. With Fringe, I’m impressed how well they are handling the relationships between the characters, some of it is very touching.