Helix - Episode 1.04 - "Single Strand": Alan struggles to save Peter, Julia finds a new ally and Doreen uncovers a dark secret. Helix airs Fridays at 10|9c on Showcase (in Canada) and Syfy (in the US).
If both promos and the extended preview are blocked in your area, you can view most of them on SpoilerTV. They have episode stills, as well.
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