  We consider a family of non-supersymmetric MQCD five-brane configurations
introduced by Witten, and discuss the dependence of the curves on the
microscopic theta angle and its relation with CP. We find evidence for a
non-trivial spectral flow of the curves (vacua) and for the level-crossing of
adjacent curves at a particular value of the theta angle, with spontaneous
breaking of CP symmetry, providing an MQCD analogue of the phase transitions in
theta proposed by 't Hooft.
