What kind of person sees someone commit suicide — and then decides to steal her identity? That's actually the most interesting question in the pilot of Orphan Black, which airs tomorrow on BBC America after Doctor Who.

Orphan Black, as you've probably heard, is BBC America's original series about clones. In the opening few minutes (embedded above), Sarah (Tatiana Maslany) meets Beth, a woman who looks exactly like her. They could be identical twins. And then the other woman throws herself under a train, leaving her purse behind. So Sarah decides to impersonate the dead woman.

But the most fascinating element of Orphan Black's first episode is that this is a show about terrible people, who have almost no moral compass whatsoever — and yet, they're still quite fascinating and entertaining. That's a tough line to walk, and lots of television shows have gone the "unlikable characters" route and ended up with people who are just unwatchably dismal — or worse yet, boring.

But Orphan Black makes it work. Sarah wants to steal Beth's life because her own life is irredeemably borked. She's stolen a shitload of cocaine from her incredibly crappy drug-dealer boyfriend, and meanwhile she left her son with a woman for a day — which turned into 10 months. Her best friend is Felix (Jordan Gavaris), a self-centered and narcissistic gay hustler.

When Sarah steals Beth's life, she no doubt hopes that Beth is a nicer person with a better existence — and Beth definitely seems to have a lot of money, although it's not clear at first how she got it. But Beth's life is every bit as much of a trainwreck as Sarah's, only in a very different way. Watching Sarah try to navigate the confusing and awful situations she finds herself in as Beth, by her wits alone, is the highlight of the episode.

By the time you get to the hints about a vast conspiracy and a ton of clones who look like Sarah and Beth, you'll already be on board for the characters alone. If you can deal with a show about people who are pretty much horrendous excuses for human beings, Orphan Black is definitely worth checking out.

Orphan Black is on BBC America tomorrow at 9 PM.