Orphan Black season 3: Where to watch premiere episode online; will new episodes lead to LEDA vs Castor clones battle?

Orphan Black season 3 premieres on 18 April on Space in Canada and on BBC America in the United States.

The official synopsis of the premiere episode titled The Weight Of This Combination, reads:

"Sarah pursues the missing Helena who is held in a faraway compound. Sarah must use her wiles — and acting chops — to deter a Topside investigator who threatens the Leda sisters' lives.

Meanwhile, Cosima appears to be rebounding from her illness, while Alison and Donnie face newfound financial woes. But when the menace of Castor rears its head once more, Sarah and her entire family must come together to survive."

As promised by an 11th hour reveal in the Season 2 finale, male clones from the militaristic Project Castor (played by Ari Millen) will shake things up for Sarah and her 'sisters,' deepening the mystery of their origins.

"The story of the male clones is really seen from Sarah's point of view, because the show has always been (her) trying to figure out what the hell is going on," co-creator Graeme Manson told USA Today. "It was really a critical part of moving the ball forward this year."

For lead actress Tatiana Maslany, the added boost of a Y chromosome in season 3 only strengthens the series' feminist themes.

"This other side of the coin is just as important, and helps to give our show different viewpoints and another experience," said Maslany. "They allow the LEDA clones to look at themselves in a different way, because the Castor clones were raised as a unit, whereas the LEDA clones were raised separate. There's a different nature/nurture perspective that we can deal with."

Orphan Black season 3, episode 1 airs on 18 April at 9pm ET on BBC America and Space.

You can click here to find out where you can watch the new episode online.