“Shake out the shiver of these dynamite bones.” So begins Coasting, the remarkably rhythmic and lyrical new work from playwright Natalie McGrath. Loaded with assonance and imagery, it is a line fairly typical of the play, in which Pearl and Ocean (Nadia Giscir and Tom Wainwright, respectively) – teenagers united by incongruity – use language as both a barrier against, and a window into, their relationship.

The opening scene certainly throws us in at the deep end: McGrath’s fast-paced blend of 80s pop lyrics and gay slang is not immediately conducive to meaning. But much like Mike Beer’s tumultuous soundscape of crashing waves, engulfing the audience at crucial moments, the dialogue is best allowed to surround and wash over you. Ears adjusting, the patois steadily builds in implication as it is urgently and bitingly delivered by Giscir and Wainwright.  We begin to develop an understanding of Pearl and Ocean’s friendship, as well as the threat posed to it by the encroaching winter – and the dead body on the beach, which Ocean may or may not know a little too much about.

Emily Watson-Howes’ immersive production allows McGrath’s disenfranchised world of seedy amusement arcades, dim bedsits and sea-view benches to totally inhabit the Bristol Old Vic Studio. Throwing the audience into the centre of the action by having the performance take place on the pit floor where the majority of the audience sit in marked-out blue blobs, as well as in the balcony, creates undeniable problems with sightlines, but is an innovative move. In fact, there is something suitably magical about being forced to accept a fractured view of this peripheral world in the midst of crisis – a view further enhanced by Emma Chapman’s slanted, dusty lighting, which lends Pearl and Ocean’s offbeat relationship the ephemeral atmosphere it deserves.

It’s a relationship of extremes – by turns combative, tender, brutal and heart-rending, and the spark between Giscir and Wainwright is tangible and charged. However, whilst Wainwright imbues Ocean with a mercurial, drug-fuelled flamboyance which rests tensely alongside a darker streak, he never quite wins the empathy of the audience in the same way that Pearl does; his vital contribution is to highlight her foibles and motivations, whilst his impetus remains less comprehensively explored. Similarly, Helena Lymbery brings regret, inner turmoil and beautifully nostalgic whisky-swilling skills to Falcon, caught between her role as Chief of Police investigating the problematic body, and potential mother figure or friend to Pearl, but the character still feels a little too expository at times. Fearing she may have got in too deep with her likely witness, she reminds us that Pearl is “a girl on the fringes of the world which [she’s] policing” – a moral sticking point the audience might have been best left to recognise themselves.

Ultimately then, it is Nadia Giscir who shines, completely encapsulating Pearl’s “wild, wild heart”, her cryptic past and her uncertain future. The second act – the more decipherable and conventionally staged of the two – requires a superlative performance from this emerging actress. She is challenged with epitomising both the hopefulness and heartbreak which emerge in the final 25 minutes, without being able to fall back on the dazzling verbal dexterity exhibited before the interval. She succeeds in spades, contributing towards a simultaneously cathartic and painful finale.

Elegiac, often funny and relevant without ever impressing a ‘message’ onto the audience, Coasting represents a dynamic new voice in the theatre. McGrath’s characters may not be perfectly balanced and her second act may lose some of the mystifying subtlety of the first, but her poeticism is uniquely, staggeringly refreshing, and is here realised in a trio of compelling performances, in a staging so absorbing it is questionable whether the same level of engagement could be achieved in any other way.