Spirit is a Boy's Own story about war and death, heroes and enemies, friends, fathers and brothers. It is a tale of childhood fantasy and aspiration, but also of adult pain and disillusionment.

With simple ease, the balsa wood planes thrown from the top of the hillside become enemy bombers, and each fighter pilot caught in the battle is a victim of the eternal male dilemma – the realisation of boyhood dreams versus an awareness of the futility of war. In this central theme, the production reminds me of the writings of Antoine de Saint Exupery – our warriors soar above the battle of life and death to engage with the metaphysical question of the endurance of the human spirit.

In this show, Improbable Theatre use many of the techniques familiar from previous productions 70 Hill Lane and Coma. Design and performance are inextricably linked: a slanting wooden structure transforms from rooftop to hillside to airplane cockpit with the sort of stunning simplicity that is characteristic of the company's work. Scale is played around with as objects take on multiple meanings. The characters melt in and out of the action, actors frequently stepping out of role to muse on the story or comment on the real-time situation.

'Every time I come on stage, someone at the back leaves,' says Phelim McDermott at one point, breaking the tension. It is this lightness of touch when dealing with serious issues that makes Improbable Theatre's work so easy to experience. In their press release, the company ask: 'Is it possible to make a show about these things that isn't po-faced and depressing?’ The answer is yes – and they have. Although I sometimes feel that they don't go as deep as they could.