‘Fringe’

For five seasons we have followed the adventures of Olivia (Anna Torv), Peter (Joshua Jackson) and Walter (John Noble) through alternative timelines and universes, and dealt with creepy “Observers” and mind-bending plot lines. Now the Friday night sci-fi staple comes to an end. Two-hour series finale, 8 p.m. Friday on Fox (seattletimes.com/tvlistings).

Also on Friday

“Portlandia,” 7 p.m. (IFC): Concerned parents Brendan and Michelle start a band that makes kids music; The Portland Nerd Council issues a Public Service Announcement; Malcom and Kris have an uncomfortable lunch at a vegan restaurant; The Feminist Bookstore hosts a comedy night.

“Undercover Boss,” 8 p.m. (CBS): Moe’s Southwest Grill President Paul Damico goes undercover and encounters a pushy restaurant supervisor.

“Nikita,” 8 p.m. (CW): Nikita learns that Sonya is Amanda’s mole and there is a second mole in Division.

“Ultimate Guide to the Presidents,” 9 p.m. (History): America emerges as a superpower; the Cold War presents the nation with the threat of nuclear annihilation; the struggle against the spread of communism abroad; the power of the presidency rises and falls; the Cold War ends; global terror networks.

“Merlin,” 10 p.m. (Syfy): Arthur is given the power to summon the dead.

The New York Times