<span>Imagine the scene: you’re in a tiny plane heading for a tropical island wedding. The only passengers are you and your ex-partner. And if that weren’t awkward enough, the pilot suffers a heart attack, mid-air and dies. </span> <span>That is the premise for </span><span><em>Horizon Line</em></span><span>, the new nerve-shredding thriller featuring Allison Williams (</span><span><em>Girls</em></span><span>) and Alexander Dreymon (</span><span><em>The Last Kingdom</em></span><span>) trapped in a nightmare scenario.</span> <span>When we meet </span><span>at </span><span>Weston Airport in Dublin, where the extensive special effects are being shot in front of a green screen, </span><span>Williams, 32, is bubbling </span><span>with excitement. It's a feeling she's had since she first picked up the script. "Usually life gets in the way – your phone's buzzing and emails coming in or whatever," she says. "That did not happen with this. I just read it continuously. I couldn't put it down."</span> <span>Williams, who played Marnie in </span><span><em>Girls</em></span><span> opposite Lena Dunham and featured in Jordan Peele's Oscar-winning horror-satire </span><span><em>Get Out</em></span><span>, plays </span><span>Sara, who has arrived for a friend's wedding in Mauritius. When she bumps into her former boyfriend Jackson (Dreymon), they spend an ill-advised night together and head off the next morning to a tiny island, their shaky transport piloted by cheery local Wyman (Keith David).</span> <span>What follows is a real-time, white-knuckle thriller, as these two ordinary folk are forced to pool resources. A case of fight or fly, you might say. "The analogy that we've used is, like </span><span><em>Speed </em></span><span>in the air – but with fewer people," laughs Williams, referring to the 1994 classic starring Keanu Reeves, Sandra Bullock a bus and a bomb. "From the minute it starts, you're like: 'There's no way they just land uneventfully!'"</span> <span>Certainly, the survival movie – Robert Redford in a yacht in </span><span><em>All Is Lost</em></span><span>, Bullock again in a space capsule in </span><span><em>Gravity</em></span><span> and Mads Mikkelsen in the snowy wastes in </span><span><em>Arctic </em></span><span>– is one genre that has, well, survived. "I think people love to be put in extreme situations," says Dreymon. "</span><span>W</span><span>e live in a time when we're so comfortable. Things just aren't putting us in that degree of danger usually. And I think there's a little part of us, as human animals, that misses that."</span> <span>Directed by Mikael Marcimain, who made the 2012 thriller </span><span><em>Call Girl</em></span><span>, </span><span><em>Horizon Line</em></span><span><em> </em></span><span>comes hot on the heels of </span><span><em>7500</em></span><span>, a Patrick Vollrath film that</span><span> starred Joseph Gordon-Levitt as a jumbo jet pilot trapped in his cockpit as terrorists take over the cabin. Yet, crucially, Gordon-Levitt's character was trained to fly. "I've always been curious: what would happen in a situation like that with someone who is one of us?" says</span><span> Williams. "What would we do? How would we all react?"</span> <span>The film also comes equipped with behind-the-scenes talent with </span><span>experience in claustrophobic thrillers. It was </span><span>scripted by Matthew Stuecken and Josh Campbell, who</span><span> co-wrote </span><span><em>10 Cloverfield Lane</em></span><span> – the follow-up to alien-monster movie </span><span><em>Cloverfield</em></span><span>. And the cinematographer was </span><span>Flavio Martinez Labiano, who </span><span>shot the equally tense </span><span><em>The Shallows</em></span><span>, in which </span><span>Blake Lively was stranded in water as a shark circles.</span> <span>Stoking the tension</span><span> is the idea that Sara and Jackson are former partners. "I mean, there's no doubt that for Jackson, Sara is the one and his heart got broken so violently when she left," says Dreymon. "It's difficult for him to see her again. And so the beautiful thing is that we start off this plane ride with this huge tension between two people."</span> <span>It's why </span><span><em>Horizon Line</em></span><span>, as extreme as it is, feels spot on. </span><span>"</span><span>We're</span><span> taking a very familiar dynamic and making it exponentially more stressful," says Williams. </span><span>"That was really appealing to me as well. </span><span>The idea of two people who have a thing together, but haven't been able to make it work. In an ideal world, they'd sit in a restaurant and try to figure out how their dynamic works best, with no extenuating circumstances whatsoever. And in this case, that's not exactly the opportunity they get."</span> <span>As Dreymon, 37, says</span><span>, putting two people in such extremes is the ultimate way to explore their depth of feeling for each other. </span><span>"Living through something like that together</span><span> forms an extremely strong bond." Though,</span><span> it should very much come with the classic movie disclaimer: don't try this at home.</span> <span>Adding a sense of</span><span> realism, at least in Williams's mind, was the fact </span><span>she's experienced her own dose of aerial terror. "It was [in] a small plane, I was with my mum </span><span>and my little brother, and we hit really bad weather. And it was not good. And I've been a bad flyer ever since," she says. </span><span>It was another reason she took on the film, says Williams. </span> <span>Her </span><span>co-star, who grew up in France, Switzerland and the US</span><span>, is a little different. He's</span><span> quite the daredevil. "I used to do skydiving when I was younger," he says.</span> <span>With so little in the way of big-screen blockbusters last </span><span>year, </span><span>you might even say </span><span><em>Horizon Line</em></span><span>'s extreme form of escapism feels like an appealing prospect right now. "If you're thinking, 'I'm really stressed out and </span><span>I need to</span><span> </span><span>relax and go see a movie', I would pick something else,</span><span>" Williams says, with a laugh. </span> <span>But if you want to be entertained and see a movie,</span><span> this, it would seem, is the film for you.</span> <span><em>Horizon Line is in cinemas across from January 14</em></span>