The fourth season of Fringe wasn't perfect. The bold decision to reboot both of the show's universes gave the early episodes a feeling of treading water; the season finale was a confusing mish-mash. But no other show on television now does as good a job of juggling lofty sci-fi concepts with thrillingly intimate human emotions. One-off episodes like ''And Those We've Left Behind'' confirm the show's place as the heir to X-Files; meanwhile, the standout dystopian flashforward ''Letters of Transit'' feels like old-fashioned pulp with a distinctively modern heart. —Darren Franich