Sky Peals review - a parable of alienation in a motorway service station

“I think my dad might have been an alien,” Adam (Faraz Ayub; Line of Duty; Screw) tells a self-help group he wanders into. What does that make him? He doesn’t feel at home anywhere – not with his family or, perhaps not surprisingly, at his job in a burger bar at Sky Peals motorway services.

And in fact he is almost homeless: his white mother (Claire Rushbrook) is moving out of their flat with her new man, to Herefordshire - "Where's that?" he asks vaguely. She wants him to pack up his things but he stays in front of his computer, transfixed, while they take his bed apart, and carries on squatting there in spite of the estate agent's warnings.

At his father’s funeral, which is taking place at his uncle Hamid’s mosque, he’s uneasy, can’t follow the prayers and suddenly leaves. “I thought I was in the wrong place,” he tells the jovial, breezy Hamid (Simon Nagra), who tries to reassure him.

Moin Hussain’s debut feature is a sci-fi-inspired parable of alienation, often agonisingly slow and lacking in dramatic tension but strong on atmosphere and there are even a few laughs. It’s set mainly in the motorway services, with its neon-lit corridors, creepy walkways and empty commercial units, shot by cinematographer Nick Cooke (One Day). Enjoy the rest of your journey, reads an encouraging notice. Lights glow and flash, car alarms blare – is Adam controlling them with his extra-terrestrial powers? - traffic whooshes past. We’re in a liminal space. Communication is difficult. But there are unexpected flashes of optimism.

Adam is extremely diffident and quiet but has a certain compelling presence. He is haunted by his Pakistani father’s last phone message on his answering machine, with its pulsing blue light. “I’m not too far away…I know it’s been a long time.” He hardly knew his dad, who left his mother 20 years previously. “I’m not sure he was ever comfortable here,” she tells him. This is echoed by his uncle, who goes further – he thought he was from somewhere else, he tells Adam. “Yes, Pakistan,” says Adam. “No, not like that. He told me he wasn’t human.”

So do Adam’s disturbing absences, when he sees flashing lights and goes into a sort of fugue state, mean that he, like his dad, is from another planet? Tara (Natalie Gavin; Passenger; pictured above with Ayub as Adam), a single mother and his new co-worker at the burger bar, refuses to be put off by his silences and erratic behaviour.

“You’re quite thoughtful, aren’t you?” she says when Adam explains that he puts the sauce, onions, cheese and lettuce on the bun first so it doesn’t fall apart when people are eating it. For a few moments at the team party organised by the irrepressibly cheerful new manager Jeff (Steve Oram, on fine form), Adam even seems to be enjoying himself, chatting and dancing with Tara. But then he has one of his funny turns, which she misinterprets.

Still, she remains a beacon of hope and doesn’t bear a grudge. I’m not normal either, she tells him. By the end of the film, Adam may be prepared to listen to her.

• More film reviews on theartsdesk