A to Z Thursdays, 9:30 p.m., NBC.

This fall has turned out to be the season of the romantic comedy on network TV, and NBC’s A to Z falls around the middle of the pack. Its biggest liability is the gimmick indicated by the title: As the narrator (Katey Sagal) explains, the show is a comprehensive account of the relationship between idealistic web designer Andrew (Ben Feldman) and pragmatic lawyer Zelda (Cristin Milioti, the mother from How I Met Your Mother), who will date for about eight months. With that inherently limited shelf life (each episode is also named for a letter of the alphabet, implying a maximum of 26 episodes), there’s little room for surprises or originality, and the first episode pretty closely follows the full narrative arc of a typical movie rom-com. Feldman and Milioti are both charming and have solid chemistry, and the supporting cast generates a few laughs, but after just one episode, Andrew and Zelda’s romance already feels played out.