When Endeavour is called to investigate what at first appears to be a freak accident at Lady Matilda's College, he uncovers a potential link between a series of peculiar incidents across Oxford, and despite Thursday's scepticism, becomes convinced the accidents are the result of foul play. Lady Matilda's meanwhile, is in the midst of a referendum campaign which will decide whether or not the college should become co-educational, and when one of their own is attacked while walking alone on the towpath, the female students become more determined than ever to keep the wolf without the citadel.