There are no images of the first world war in Sound&Fury’s commemorative installation. So acquainted are we with the iconography of trenches, mud and barbed wire that the absence is more powerful than any number of poppies or corpses. Unseen, the horrors of conflict become all the more haunting.

Charlie Ward attempts instead to enter a shell-shocked imagination. Lying in a row of beds, an audience of 10 is transported to a wartime hospital, surrounded by its busy hum of noises. Dan Jones’s intimate sound design takes us into the mind of Harry, a wounded soldier drifting in and out of consciousness, moving between memory and trauma. In one moment, his mother’s voice is whispering tenderly in our ears; in another, the room vibrates with the impact of an exploding shell.

The eponymous Charlie is Chaplin, whose films blur with Harry’s fragmentary recollections. Inspired by the discovery that Chaplin’s films were shown to recovering soldiers during the war – projected on to the ceilings of hospital wards – Sound&Fury have done the same here. Short clips of clowning are interspersed with periods of utter darkness, combining to create a surreal sense of disorientation. Slapstick comedy slowly gives way to something more unsettling.

Compared with some of the other artworks in the 14-18 NOW programme – Paul Cummins and Tom Piper’s huge wave of ceramic poppies, or Jeremy Deller’s countrywide We’re Here Because We’re Here – Charlie Ward is a slight thing. Running at 15 minutes, it’s fleeting and dreamlike but like the most arresting dreams, it lingers in the mind long after waking up.

• At York Army Museum until 4 October. Then touring.