Halder (David Tennant) is a "good man", an expert in German literature, but he lives in German during the rise of the Nazis and C P Taylor's fascinating play explores how a good man gets sucked in to an evil path. Halder doesn't make friends easily but has one lifelong friend, a Jew called Maurice (Elliot Levey) and a mother (Sharon Small) who has gone bind - and so we have an environment in which we can explore the Nazi attitudes to "being German", disability and Jews. And what an exploration this is - so powerful in the subtle way Halder gets nudged towards his eventual role as an SS officer, justifying each small step in logical but ultimately wrong-headed arguments.
With Levey and Small playing all the parts except Halder and with physical props largely replaced with "sound props" the play can move at a fast pace, but this is also what niggles in the end. Too many characters overlapping and getting mixed up despite the sterling efforts of all on stage to differentiate them.
With one of the most powerful endings I have seen in recent years, bringing the character of Halder (and the audience) face to face with where his journey has taken him, this is a powerful, memorable, disturbing play and well worth a visit.