Photo: FOX

You might be forgiven, if it wasn’t your job to watch it, for thinking that Sleepy Hollow is all about the adventures of a time-traveling Ichabod Crane (played by Tom Mison) in the modern world. And true, he’s the one whose son is in cahoots with a sinister guy named Moloch to usher in the end of days and whose wife has been taken to parts unknown by one of the four horsemen of the apocalypse (who, side note, is also the Headless Horseman we know from the Washington Irving tale as well as Crane’s wife’s former fiancé). But fans of Sleepy Hollow, which continues its second season tonight on Fox at 9 p.m., know that there would be no show without Lieutenant Abbie Mills. One of the sci-fi drama’s most distinct pleasures is watching Crane and Mills — the latter played by Nicole Beharie — exhibit a deep-seated and reciprocal need for one another. Here are five reasons Beharie is nobody’s sidekick.

1. Like Crane, she’s got skin in the game.

Crane’s goal from episode one has been to reunite with his wife, Katrina. While he’s pursued her with a romantic single-mindedness (at least up until the finale, when he basically told Katrina and Abbie he’d figure out a way to keep both of them out of purgatory), Abbie’s personal investment in the plot is equally noble. Her sister was put in an asylum because she refused to confess to seeing Moloch in the woods years ago, while her mentor and father figure Sheriff Corbin was killed by the same otherworldly forces. So far, Crane and Abbie have been able to work together toward their uncommon goals. It’ll be interesting to see if the twosome ever wind up as adversaries as conflicts of interest potentially arise.

2. She brings a different skill set to the table.

Crane’s got a photographic memory and is a former Oxford history professor; Abbie grew up with both supernatural-encounter experience and, you know, the internet. The standard sidekick’s job, to ask plot-advancing questions of the main protagonist, has been divvied up even-Steven between Crane and Abbie, in a way not unlike Mulder and Scully on The X-Files. These two truly embody the old adage that two heads are better than one. (Insert your best Headless Horseman joke here.)

3. She and Crane are on each other like glue.

They got put under by a shaman together, entered purgatory together, and even argued the pros and cons of ending Crane’s life together (when he was willing to die in order to put an end to the Horseman’s life as well). Abbie and Crane don’t have internal strife that comes out in soliloquy close-ups. They hash everything out in dialogue. They’re not just detective-genre buddies; they’re devout disciples of the buddy system.

4. She’s not the comic relief; he is.

Abbie may be the most all-business woman on TV. Her out-and-out seriousness makes Olivia Pope seem like Phoebe Buffay. She’s neither the dimwitted hanger-on nor the out-of-her-league junior cohort. In fact, there really aren’t many characters around (black, white, male, female) who just are who they are and do what they do like Mills, without any superfluous details, silly backstories, or quirky-for-the-sake-of-it tropes. (That means you, Mysteries of Laura!)

5. Hello! She’s played by Nicole Beharie!

Can we stop a second and give this actress some due? If you saw Beharie’s portrayal of Jackie Robinson’s wife in 42, then you know she’s incapable of background acting.