Lyric theatre, Belfast Lucy Caldwell freights her well-observed Chekhov adaptation with the tensions of 1990s Belfast, adding to the siblings' sense of stifled isolation "We can't stand it here. The sky is grey and the streets are grey." In Lucy Caldwell's new version, Chekhov's Three Sisters are transposed to 1990s Belfast, and are the daughters of a British army officer. With both parents dead, Orla (Julie Maxwell…