With another great episode, Orphan Black slows things down a little to re-establish the various factions and conflicts we need to be aware of going forward.

Now that Helena has been revealed to be alive, we get to meet some new Proletheans and say goodbye to Tomas. This episode also sees the return of Mrs S, and it piles on the surprises in effective ways.

One development that doesn’t come as a surprise is that Alison’s life is suddenly spinning out of control. Orphan Black doesn’t keep the identity of Alison’s real monitor secret for long. While she seemed relatively calm in last week’s episode, the realisation that she allowed Aynsley to die for no reason is devastating. It’s made worse by Felix, who has become her emotional support, running off with Sarah and Kira at the episode’s end.

For Sarah, this is an exceptionally fast-paced episode. Once again, the show doesn’t keep its secrets for long, revealing that Kira is safe and had been with Mrs S – who now seems to referred to as just ’S’ – all along. Mrs S draws Sarah out and gets her back to Kira, but it’s clear that everyone is holding back from telling the truth.

Wisely, Orphan Black has brought Art into the ‘Clone Club’. Although he doesn’t get much to do this week, it’s obvious the cop plots will continue to be central to the overall narrative. Art has definitely established a trustworthy connection with Sarah but his unwillingness to tell Angela what’s going on will send her off to investigate the situation on her own.

There’s rather a lot of vague setup in this episode, but the main beats are clear. Tomas represents a less nuanced kind of Prolethean and is killed so that new characters – like leader Henrik Johanssen (Peter Outerbridge) – can bring Helena into their family and, presumably, become more of a threat than the Proletheans have previously been.

The developments of Cosima’s story are intriguing, and it’s always fun to see two clones meet who haven’t met before. There’s not much to say about this yet but it’s safe to assume Dyad are still keeping loads of secrets from Cosima even if Dr Leekie is prepared to give her a lab for her research. Everyone’s clearly very interested in exactly how Sarah had a child and whether Helena will be able to also, making that perhaps the show’s most central mystery.

All Sarah’s interested in, though, is keeping herself, Kira and Felix alive. In the interest of survival, she flees from Mrs S (who can’t even seem to trust the people she’s been relying on for years, her “old network”) and goes on the run. This week’s story is more disconnected than last week’s and it’s always more satisfying when the clones get to interact and work together.

Sending Sarah away, at least temporarily, should shake up the dynamic though, and both Alison and Cosima are in increasingly difficult situations where they’re going to feel more and more trapped by circumstance. And, there’s always the threat of Helena and the Proletheans just waiting to be unleashed.

While this is a plot-heavy episode that necessarily is a little slower, it still displays urgency and great pacing, setting up some exciting conflicts for the rest of Season 2.

Aired at 10pm on Wednesday 7 May 2014 on BBC Three.