A group of bored students hang out at a bus stop. Zombie like, threatening. Kester (13) and Polly (15) Parish approach. It’s their fifth new school in five year thanks to their Mum’s job. They’re tired of the constant changes. Kester is confident with strangers and teases Polly about her shyness. Polly is reading a self-help book and confesses she’s not sure whether the book is making her shyness worse or not.

The queue dissolves into their new school, which doesn’t seem like what they remember from their tour. After some confusion, they are shown into a classroom by the Caretaker. Mr Morton, the teacher arrives and makes the class give a ‘reason register’ reminding students why they must attend school. One by one, the students recount tragic accidents which resulted in their deaths and subsequent enrolment at The Other School.  Polly and Kester are horrified. They don’t have a reason, so are sent to the Head office in the company of a pupil called Daniel, who doesn’t believe the school exists. They encounter the class bullies, Axel, Wilkes and Leonard; but are rescued by the Caretaker.

At the office, the secretary reveals Kester has a place at the school and gives him his ‘reason’. There is no reason for Polly, so she is sent through to the Headmistress’ office to sort out why. The Headmistress breaks the news that although Polly is still alive, Kester is indeed dead, having been hit by a bus. Polly has ended up by mistake at The Other School, where lost souls are educated in the afterlife until they progress to ‘higher education’. Polly is distraught and the Head gives her a special pass, making a bargain with her that if she doesn’t tell anyone, she can come and go as she pleases.
In a hospital somewhere, Ms Parish (Polly and Kester’s mum) is approached by a Doctor. Polly is nearby in a bed and although unresponsive, going to be okay. The Doctor advises Ms Parish that Polly is still in shock and is likely to progress through the stages of grief (Denial, Depression, Anger, Bargaining, Acceptance) as she comes to terms with her brother's death. The Doctor promises to try and get hold of Polly’s Father. Left alone, Ms Parish begs Polly to come out of shock so they can begin grieving together.

Back in the Other School, Kester is cheered up by the Other students, who show him the potential an afterlife can afford. Polly enters and is horrified. She tries to get Kester to leave, but he refuses, accusing her of being her typical social outcast self. The two fight  and it is revealed Polly got most of the attention from their Mother when their Father left the family.

Polly is left crying on her own and is comforted by the Caretaker. When she shows him the Head’s pass he becomes angry, telling her to leave and not come back. He explains the history of the school, revealing it is indeed ‘not there’ and only exists in Polly’s head. She must leave soon or she may find herself inventing more reasons to stay. The reality of the school breaks down and Polly finds herself at Kester’s funeral. Kester appears and after apologizing for fighting, asks Polly if she will return to school with him. Ms Parish (obviously unseeing Kester) beckons Polly to go with her. Act I ends with Polly deciding if she will abandon her pass and face real life or not.

Act II begins in the real and Other world, six months after Act I ended. Polly has kept the pass and is managing to live in two places at once. She’s attending therapy in the real world, while in the Other School, classes go on as normal. Ms Parish is unhappy and feels she’s losing her daughter. The doctor rings to tell her they have found her ex-husband if she would like to see him. Ms Parish talks with Carol, a neighbour, about how she blames constantly changing lifestyles for her marriage breakdown and distance from her children. Carol offers to introduce her son, Barney, to Polly.
Barney (15) discovers Polly reading her self-help book. He is equally socially awkward, but suggests they follow the books advice and get out of the house together. After dull trips to a playground and bowling alley, Polly’s personality starts to emerge and she suggests a trip to the cinema. Here they are confronted by alpha females, Sarah Sidcup, Janine and Ellen. Sarah teases Polly about her brother's death and Polly reacts badly, shouting at Barney and retreats into her head when she can’t remember what Kester’s motto was.

Back in the Other School, Polly is greeted by Kate the Dinner lady. Polly finds Kester is not well, he’s going almost Zombie like. He recovers when he sees Polly, but suggests she is finding the real world more interesting than him. Polly insists that’s not the case and they have fun recounting memories of childhood. After the song, Kester regresses again and Polly drags him off in search of answers.

Somewhere in the Other School, Axel has been caught trying to escape by the Caretaker. The Head reveals a nastier side and punishes both of them. Polly arrives with Kester. The Head diagnoses Kester as ‘fading’ because his life force is tied to Polly’s. If she will give up her pass and remain in the Other School forever, Kester will survive. Polly is about to give up the pass, but Axel grabs her and they escape. They head for the school gates.

Axel wants Polly to take all of the students away from the Other School. For the first time, Polly is popular. She uses the pass and a school bus arrives – with no driver. The students bundle on and Kester is lost in the scrum. Polly tries to stop, but Axel takes over and starts the bus. Polly fights with him to return to school and the bus crashes, destroying the school. At the same time in the real world, Polly has wandered into the middle of a road and is close to being run over. She is rescued by her Mum.

Polly admits to her Mum how dangerous the Other School has become and yet how terrified she is to let it go. Her Mother gently encourages her, giving her a chain that was a present from Kester’s Dad to him.. Polly works up the courage to return to the Other School one more time to say goodbye to her brother.

The Other School lies in ruins  the Head is furious and the other students behave like Zombies in her presence. Polly regains control of her mind and Kester appears. Before Polly says goodbye, she asks her brother how to be confident like he was. He replies it was her love for him that gave him the confidence to be so daring. With that, the whole school offers parting advice and disappears.

It’s a new school year. Polly is returning to school for the first time, nervous, but with her new friend Barney. Ms Parish has reconciled things with Polly’s Dad and is arranging visitations. Sarah Sidcup, Janine and Ellen enter and pick on Barney. Polly stands up for him but they taunt her about the accident. Polly describes details of Kester’s death and, while upset, remains in control. Not so Sarah who runs off, distraught. Janine and Ellen are impressed and accept Polly and Barney as people to be respected. As Polly gets on the bus, Kester appears watching over her from an unseen place.