The art professor's labours have just uncovered an area of the painting that graphically portrays Herod's massacre of the innocents with soldiers slashing and a river red with blood. The co-presence of this scene is embarrassing, according to the academic, because it imputes a certain guilt to the holy child, showing him willing to sneak away and leave the nightmare to others. This position, it turns out, is one with which the art professor is all too familiar. A Jew who has suppressed his identity in order to establish a career in anti-Semitic academe, he is now - as racial hatred erupts in pogroms and boycotts, with much worse to follow - preparing to take up a cushy post in New York.
From all this, you might be led to expect that the eponymous painting would prove to be as rich and dense in its thematic implications for the drama as the Giotto-anticipating fresco was in David Edgar's Pentecost. But sustaining metaphors is not Garner's forte, nor - to judge from John Dove's production - is sureness of focus. Indeed, I heard people on the way out complaining that The Flight into Egypt seemed like two plays joined at the hip.
Act 1, set in Lacznic in 1939, shows us the tensions of life for the Jews there through the experiences of one family. They find themselves the subject of inexplicable (and clumsily dramatised) visits from the art professor (Paul Jesson) who, though a "gentile", seems partial to the Jewish food that he purchases from them. What else does this stranger want? Is he a provocateur? To the teenage children (Aidan McArdle and the excellent Paloma Baeza), he eventually confesses his Jewishness but, by this time, his visits have raised fatal suspicions among the townsfolk.
Only the daughter of the family, paralysed with fear behind the door, survives the butchering raid. Act 2 switches to the story of how this young woman, a talented artist, is hidden throughout the war in the basement flat of working-class Krasinski, whose shy, unassuming goodness is most uncloyingly well conveyed by Con O'Neill. The play effects an over-obvious contrast between Krasinski, who has selflessly risked his life for the girl, and the guilt-salving art professor, who breezes back to Poland after the war, wanting to whisk her away to a new life in New York.
Mr O'Neill and Ms Baeza are very touching as they enact the silent, stealthy rituals of a fearful existence in hiding. They also beautifully hint at unspoken love. It's a back-handed compliment, though, to claim that the best bits of The Flight into Egypt are wordless.
n At the Hampstead Theatre, London NW3 to 5 Oct (0171-722 9301)Reuse content