midnight
In case of need , they can protect him , and bear witness in his favour . He is not capable of much feigning ; he must only join the meeting shortly before midnight ; thus he will have no need to speak . Our guards will wait in the Grove of Constantinus , at the back of Photius 's house . At midnight -- the trumpet sounds when the guard is relieved , and you know that it can be distinctly heard -- we shall break in . Belisarius , therefore , need not undertake the dangerous task of giving a signal . '' `` And you -- you will be sure to be there ? '' `` I shall not fail .