What if you discovered that you were the property of a multinational corporation? That it held exclusive rights to the very essense of your being - your unique genetic code?

What if you found out, you weren't born but man-made? That you are one of nine identical people constructed in a lab?

That's one of the terrifying truths Sarah Manning (Tatiana Maslany) has to face in BBC America's Orphan Black, a superb, exciting and intelligent sci-fi thriller which returns for its third season 9 p.m. Saturday.

One of the most compelling genre offerings on TV this decade, Orphan Black is one of two sci-fi/fantasy shows offered this weekend by BBC America.

Tatau, an exotic, mystical murder mystery set in the Cook Islands will have its season premiere 10 p.m. Saturday.

Of clones beautiful & strange

Created by two Canadians, writer-producer Graeme Manson (Cube) and director John Fawcett (Ginger Snaps), Orphan Black has become such a cause celebre, the third season premiere will be shown not only by BBC America but all its sister channels, including IFC, AMC, SundanceTV and WEtv.

Folks new to the sleeper hit can catch up with the story with a marathon screening of the first two seasons (20 episodes in total) starting midnight Friday on IFC.

Orphan Black is a nightmarish, sometimes surreal, sometimes crazy-funny, look at what the future might look like when biotech advances make human cloning a reality.

The story is told largely through the eyes of Sarah Manning, a school drop-out, single mother and general ne'er-do-well. In the pilot episode, she witnesses a woman commit suicide by speeding train, a woman who could be her identical twin.

Within days, Sarah sees another identical twin shot to death, then meets a handful of other carbon copy women. They include soccer mom Alison Hendrix, Cosima Niehaus, a bisexual PhD student in evolutionary biology and Helena, a Russian-born assassin who has been tasked by a fantatical religious cult with killing all her sisters, all played by Maslany.

That's because the women are unnatural - they are clones, part of a batch of nine cooked up by a biotech firm called the Dyad Institude - whose head, Rachel, is yet another clone.

Canadian actor Maslany (Heartland, Being Erica) delivers one of TV's greatest performances as the clones, each of whom has a distinct personality and her own special kind of weirdness.

Sarah emerges as our heroine because of her uniquely willful nature. She's a free spirit who can't abide rules. Her sisters, on the other hand, have been monitored their entire lives by Dyad - their friends, husbands, lovers often turn out to be Dyad agents.

We enter the third season following a shocking discovery that adds a delicious new dimension to the series: Dyad is only one of two cloning projects. The other, called Project Castor, is a military operation which has been pumping out male soldier clones.

Murder in the South Pacific

Kyle Connor (Joe Layton), the hero of British import Tatau, is one of those naive, obsessively earnest good guys you want to smack upside the head. A cheasier version of the Hitchcockian Everyman, Kyle becomes convinced early in the pilot that he has witnessed a murder. And he just won't stop talking about it.

A pair of Londoners both keen to leave their lives behind, Kyle and his BFF Budgie (Theo Barklem-Biggs) plan to get jobs in New Zealand, but before getting down to it, they take a holiday in the nearby Cook Islands. The locale is exotic, the women beautiful and the local bartender (Barry Atsma) eager to help the boys have a great time.

To help them loosen up, he has them take a locally-brewed hallucinogen.

Out of his mind tripping, lost in the thick jungle, Kyle is approached by a stunning local woman (Shushila Takao) who begs him to save her.

Next morning, he finds her dead body in the ocean.

Trouble is, she's no longer there when Kyle returns with the cops. He's convinced the entire island, including the girl's parents, conspired in her murder.

Then one fine morning, Kyle meets the girl - she's alive and well.

That's when an already weak show and its incredibly annoying hero become even more grating: Kyle immediately decides his visions of the young woman actually were prophetic. She may not be dead now, but she will be!

Tatau at times is diverting. Visually, it's simply gorgeous. But the story? Give me a break.