Must-see winter finale of “Fringe” tonight (9 p.m., Fox). Executive producer Jeff Pinkner, who co-wrote the episode, said it’s the best one yet… and the one coming back (in April) is even better.

The episode’s official description:

“Worlds collide with unthinkable results in the FRINGE winter finale. A Manhattan office building is rattled to its core, leaving only one survivor (guest star Jim True-Frost), and the Fringe Team examines his otherworldly origins. Once Walter (John Noble) surmises that what shook the building was something he discovered many years ago, the team races to Jacksonville to help Olivia (Anna Torv) reconnect with her past in order to avert what they fear will happen next.”