I expected The Other School to be a zany horror-comedy-musical about two students, Polly and Kester Parish, getting caught up in a paranormal adventure at a nightmarish educational establishment. It turns out to be a story with far more complexity and emotional depth.

Polly Parish and her brother Kester arrive for their first day at a new school, one of many first days at new schools since they move around so much. There is a piquant bickering rivalry between Polly (Lizzie Jay) and Kester (Oscar Morgan). Polly, though older, is the shyer of the two, and Kester teases her about reading a book on coping with social anxiety disorder. But their teasing is underpinned by real affection, and they become each other's support as they find themselves in the oddest school they've ever known.

Polly and Kester have two striking duets together, "It's Okay to Be You" and "Do You Remember?", each equally stunning and with very different emotional resonance. The warmth in Polly and Kester's relationship underpins the whole performance, setting the tone for the rest of the cast.

The song "How I Got to School" is a toe-tapping number where the class take it in turns to explain how they arrived in this bizarre place: crushed by a woman jumping to her death, run over by an ambulance, hit by a clay pigeon, and so on and so forth. Seeking answers, Polly and Kester are led on a tour around the school by Daniel (Tony Turpin) who explains that "If It Were There", that's where the library, gym, and canteen would be - but none of it is real. This is my favourite number, displaying Tim Jackson's choreography to superb effect with the ensemble creating walls, doors, football goals and a rather queasy lunch line with crisp efficiency and full-on energy.

It becomes clear that Kester is meant to be at the eponymous "Other School" but Polly is not, and this is where the show becomes increasingly cerebral: we find Polly's mother, Ms Parish (Ellie Hudson) in a hospital waiting for her daughter to wake up from the concussion she suffered when Kester had the accident that killed him. Ms Parish's song "Hospital" is intense with the thrumming emotion of a grieving mother.

The ensemble picks up the pace again with "It's a Fine Life (When You're Dead)," featuring choreographic stylings that can only be dubbed zombie-chic and which I hope to see become the next big dance craze. There is some charming tap work here as well.

Other standout moments in the first half include a beautifully staged funeral with the cast making a coffin out of plastic school chairs and a meditation on conflicts between "Head and Heart", delivered with a sweet sentimentality by The Caretaker, Alex Gilchrist. Freddie Tapner gives us a deliciously ghoulish teacher, Mr Morton, who leads the way into the second act with "Mr Morton's Interesting Facts about Death."

The second half is more focused on Polly's real life outside the "Other School," which is a coping mechanism she is using to deal with her brother's death. In comes Barny, an irrepressibly peppy Robin Franklin, who makes it his mission to help Polly reintegrate into society with only the slightest prompting from his mother Carol (Jess Stoddard).

As well as learning to let go of the "Other School," Polly must negotiate some bullies – "large female predators," as Barny calls them – in her new school. The interplay between Polly and her aggressors is fantastically funny and cringe-making. The show culminates with a tense action scene where Polly must learn to accept her brother's death and to move forward without guilt.

The ensemble as a whole is terrific, and I regret I can't praise by name every actor as they each approach the production with gusto. The pacing of the show works well and the cast display an impressive emotional range. The live band too are excellent, providing energetic and feeling support to the cast onstage.

Those with an eye for design will enjoy the simple but effective set pieces from Colin Falconer and the atmospheric lighting by Howard Hudson. The "Other School's" alarming orange uniforms really fit the mood of the show.

There are a few moments where youthful voices struggle to provide the full power needed to support the big ballads. The songs require an ambitious range and, apart from these minor slips, the performers carry them off with aplomb.

After the show's thunderous applause finally dies down I overhear some nabob in the audience exclaiming wistfully, "I ALWAYS wanted a first night like that!" Well, quite. My companion for the evening and I wended our way to the station merrily singing the chorus to "How I Got to School".

The Other School, at St. James TheatreCaitlin McDonald reviews The Other School at the St. James Theatre.4