The North Star’s crew and Ben make a surprising discovery while out hunting for signs of whatever took away their friend Chris. Meanwhile Ryn takes refuge with Helen, and Sheriff Bishop puzzles over the murder of a local ne’er do well.

So let’s be honest, the pilot episode of the show didn’t exactly blow me away, mainly because it felt like all the right resources were being thrown at something with at best sub-par, hokey writing. So the question is, why is this second episode of Siren so compelling?

Partly it’s down to the fact that star Eline Powell is a genuinely magnetic presence to watch on the screen. She doesn’t say much, and at the end of the day she’s a slight thing, dwarfed by the rest of the cast around her, but she manages to convey an air of menace and danger far outside her physical frame, as well as the very alien nature of the creature she’s portraying.

The rest of the cast are killing it as well though – despite the fact that the script is still quite hokey, they’re all committing to it 100% from start to finish. And they’re a finely talented bunch as well. Whether it’s Fola Evans-Akingbola’s Maddie coming to terms with the fact that mermaids are real based on her boyfriend’s assertions and some grainy underwater footage; or Rena Owens’ Helen Hawkins lecturing Ben about the reality of mermaids and the murky past of his ancestors or confronting Ryn herself, everyone is delivering their lines not just with sincerity, but actual conviction, which combines with decent FX work and beautiful locations to overcome the silliness of the central premise.

And it’s a good job too because that central premise is as daft as you’re likely to see on genre TV this year. Mermaids are real. The military (and by extension presumably the government) knows this, and sends a team to capture one on the basis of an emergency call from some fishermen about an injured crew member, then ships it and said crew member to a top secret research facility where a heavily conflicted scientist can perform excruciating tests and take samples from it to experiment with the potential properties of its biology. Meanwhile, the fishermen are upset that their friend is missing and will try to track him down and take on said top secret military project in the process, and the somehow be-conscienced son of the town’s ruling family will try and help another mermaid to find her ‘sister’ at the same time as trying to help his fishermen buddies find their missing friend, all while taking advice from the town eccentric who nobody believes about anything.

But it works. It genuinely, honestly does. That earnestness with which all the cast engages, that FX work, the fantastically otherworldly performance of Powell – which is only helped by the way in which the other cast members go with it – all combine to make something that sounds terrible on paper but is oddly fascinating to watch unfold on the screen. I said last time that maybe this show had more to give, and I worried that maybe it had shot its bolt of surprises in its opening hour. I’m happy to confirm I was right on the first point and completely wrong on the second.

Verdict: An insanely daft central premise flies thanks to a rock solid cast, committed performances and great visuals. One of the year’s more pleasant genre surprises. 8/10

Greg D. Smith